Last visit was: 19 Nov 2025, 13:31 It is currently 19 Nov 2025, 13:31
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
avatar
giobas
Joined: 09 Sep 2016
Last visit: 09 Nov 2017
Posts: 32
Own Kudos:
309
 [108]
Given Kudos: 10
Location: Georgia
Concentration: Finance, International Business
GPA: 3.75
WE:Analyst (Finance: Investment Banking)
Posts: 32
Kudos: 309
 [108]
23
Kudos
Add Kudos
84
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 19 Nov 2025
Posts: 105,390
Own Kudos:
Given Kudos: 99,977
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,390
Kudos: 778,350
 [19]
7
Kudos
Add Kudos
11
Bookmarks
Bookmark this Post
User avatar
quantumliner
Joined: 24 Apr 2016
Last visit: 26 Sep 2018
Posts: 242
Own Kudos:
779
 [8]
Given Kudos: 48
Posts: 242
Kudos: 779
 [8]
2
Kudos
Add Kudos
6
Bookmarks
Bookmark this Post
General Discussion
avatar
nainy05
Joined: 10 Nov 2016
Last visit: 19 Sep 2021
Posts: 45
Own Kudos:
21
 [1]
Given Kudos: 64
Location: India
GMAT 1: 730 Q50 V39
GMAT 1: 730 Q50 V39
Posts: 45
Kudos: 21
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
quantumliner
The Three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?

Two points to be known about a Right Angled Triangle

The height and the hypotenuse of Right Angled Triangle will always be Odd Integers
The Base of the Right Angled Triangle will always be an Even Integer

Statement 1) the perimeter of the triangle is an odd integer.
Based on the above, the perimeter of a Right Angled Triangle will always be Even. Hence the Triangle in question is not a right Angled Triangle. This statement is sufficient.

Statement 2) if the triangle's area is doubled, the result is not an integer.

The Area of a Right Angled Triangle is 1/2 * b*h. On doubling this it becomes b*h. Since all sides of a Right Angles Triangle are integers, b*h will also be an integer. So in this case, the Triangle in question is not a right Angled Triangle. This statement is sufficient.

Answer is D


Consider : 6,8,10... These also form right angled triangle.
So,I think reasoning for St 1 may not be correct...
User avatar
satsurfs
Joined: 07 Jan 2015
Last visit: 19 May 2024
Posts: 49
Own Kudos:
158
 [1]
Given Kudos: 666
Location: United States
GPA: 3.4
WE:Engineering (Manufacturing)
Products:
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
nainy05
quantumliner
The Three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?

Two points to be known about a Right Angled Triangle

The height and the hypotenuse of Right Angled Triangle will always be Odd Integers
The Base of the Right Angled Triangle will always be an Even Integer

Statement 1) the perimeter of the triangle is an odd integer.
Based on the above, the perimeter of a Right Angled Triangle will always be Even. Hence the Triangle in question is not a right Angled Triangle. This statement is sufficient.

Statement 2) if the triangle's area is doubled, the result is not an integer.

The Area of a Right Angled Triangle is 1/2 * b*h. On doubling this it becomes b*h. Since all sides of a Right Angles Triangle are integers, b*h will also be an integer. So in this case, the Triangle in question is not a right Angled Triangle. This statement is sufficient.

Answer is D


Consider : 6,8,10... These also form right angled triangle.
So,I think reasoning for St 1 may not be correct...








Is it safe to say that the perimeter of a right triangle is always even?
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 19 Nov 2025
Posts: 105,390
Own Kudos:
778,350
 [3]
Given Kudos: 99,977
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,390
Kudos: 778,350
 [3]
1
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
satsurfs
nainy05
quantumliner
The Three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?

Two points to be known about a Right Angled Triangle

The height and the hypotenuse of Right Angled Triangle will always be Odd Integers
The Base of the Right Angled Triangle will always be an Even Integer

Statement 1) the perimeter of the triangle is an odd integer.
Based on the above, the perimeter of a Right Angled Triangle will always be Even. Hence the Triangle in question is not a right Angled Triangle. This statement is sufficient.

Statement 2) if the triangle's area is doubled, the result is not an integer.

The Area of a Right Angled Triangle is 1/2 * b*h. On doubling this it becomes b*h. Since all sides of a Right Angles Triangle are integers, b*h will also be an integer. So in this case, the Triangle in question is not a right Angled Triangle. This statement is sufficient.

Answer is D


Consider : 6,8,10... These also form right angled triangle.
So,I think reasoning for St 1 may not be correct...

Is it safe to say that the perimeter of a right triangle is always even?

If the lengths of all three sides are integers (so if a right triangle is Pythagorean Triple triangle), then yes the perimeter will always be even.
avatar
PMZ21
Joined: 25 Apr 2017
Last visit: 24 Jul 2017
Posts: 13
Own Kudos:
Given Kudos: 136
Posts: 13
Kudos: 13
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi Bunuel,

Could you please share the solution for this? I'm very confused!
User avatar
Nunuboy1994
Joined: 12 Nov 2016
Last visit: 24 Apr 2019
Posts: 558
Own Kudos:
Given Kudos: 167
Location: United States
Schools: Yale '18
GMAT 1: 650 Q43 V37
GRE 1: Q157 V158
GPA: 2.66
Schools: Yale '18
GMAT 1: 650 Q43 V37
GRE 1: Q157 V158
Posts: 558
Kudos: 124
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
poojamathur21
Hi Bunuel,

Could you please share the solution for this? I'm very confused!

The three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?


(1) The perimeter of the triangle is an odd integer.

Given p + q + r = odd. This implies that either all three p, q and r are odd OR two of them are even and the third one is odd.

If all three p, q and r are odd, then \((side_1)^2 + (side_2)^2 = odd+odd=even\) and \((side_3)^2=odd\). Thus \((side_1)^2 + (side_2)^2 \neq (side_3)^2\). The triangle cannot be right angled.

If two of them are even and the third one is odd, then \((side_1)^2 + (side_2)^2 = even+even=even\) and \((side_3)^2=odd\) OR \((side_1)^2 + (side_2)^2 = even+odd=odd\) and \((side_3)^2=even\). In any case \((side_1)^2 + (side_2)^2 \neq (side_3)^2\). The triangle cannot be right angled.

So, we have a definite answer to the question: the triangle is NOT right angled. Sufficient.

From above we can derive that if the lengths of all three sides of a right triangle are integers (so if a right triangle is Pythagorean Triple triangle), then the perimeter of the triangle must be even.

(2) If the triangle's area is doubled, the result is not an integer.

If the triangle were right angled, the area would be \(\frac{(leg_1)*(leg_2)}{2}\) and double that would be \(2*\frac{(leg_1)*(leg_2)}{2}=(leg_1)*(leg_2)=integer*integer=integer\). Since we are told that double the area of the triangle is NOT an integer, then the triangle is NOT right angled. Sufficient.

Answer: D.

Hope it's clear.

Bunuel my interpretation of your explanation is that if the pythagorean theorem cannot be validated then the triangle cannot be a right triangle- because the Pythagorean Theorem only applies to right triangles?
avatar
adityapareshshah
Joined: 17 Apr 2016
Last visit: 14 Nov 2017
Posts: 60
Own Kudos:
Given Kudos: 254
Posts: 60
Kudos: 46
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
poojamathur21
Hi Bunuel,

Could you please share the solution for this? I'm very confused!

The three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?


(1) The perimeter of the triangle is an odd integer.

Given p + q + r = odd. This implies that either all three p, q and r are odd OR two of them are even and the third one is odd.

If all three p, q and r are odd, then \((side_1)^2 + (side_2)^2 = odd+odd=even\) and \((side_3)^2=odd\). Thus \((side_1)^2 + (side_2)^2 \neq (side_3)^2\). The triangle cannot be right angled.

If two of them are even and the third one is odd, then \((side_1)^2 + (side_2)^2 = even+even=even\) and \((side_3)^2=odd\) OR \((side_1)^2 + (side_2)^2 = even+odd=odd\) and \((side_3)^2=even\). In any case \((side_1)^2 + (side_2)^2 \neq (side_3)^2\). The triangle cannot be right angled.

So, we have a definite answer to the question: the triangle is NOT right angled. Sufficient.

From above we can derive that if the lengths of all three sides of a right triangle are integers (so if a right triangle is Pythagorean Triple triangle), then the perimeter of the triangle must be even.

(2) If the triangle's area is doubled, the result is not an integer.

If the triangle were right angled, the area would be \(\frac{(leg_1)*(leg_2)}{2}\) and double that would be \(2*\frac{(leg_1)*(leg_2)}{2}=(leg_1)*(leg_2)=integer*integer=integer\). Since we are told that double the area of the triangle is NOT an integer, then the triangle is NOT right angled. Sufficient.

Answer: D.

Hope it's clear.

Hi Bunuel,

Can you please explain why the triangle is NOT right angled, if the area of the triangle is not an integer?
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 19 Nov 2025
Posts: 105,390
Own Kudos:
Given Kudos: 99,977
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,390
Kudos: 778,350
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Nunuboy1994
Bunuel
poojamathur21
Hi Bunuel,

Could you please share the solution for this? I'm very confused!

The three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?


(1) The perimeter of the triangle is an odd integer.

Given p + q + r = odd. This implies that either all three p, q and r are odd OR two of them are even and the third one is odd.

If all three p, q and r are odd, then \((side_1)^2 + (side_2)^2 = odd+odd=even\) and \((side_3)^2=odd\). Thus \((side_1)^2 + (side_2)^2 \neq (side_3)^2\). The triangle cannot be right angled.

If two of them are even and the third one is odd, then \((side_1)^2 + (side_2)^2 = even+even=even\) and \((side_3)^2=odd\) OR \((side_1)^2 + (side_2)^2 = even+odd=odd\) and \((side_3)^2=even\). In any case \((side_1)^2 + (side_2)^2 \neq (side_3)^2\). The triangle cannot be right angled.

So, we have a definite answer to the question: the triangle is NOT right angled. Sufficient.

From above we can derive that if the lengths of all three sides of a right triangle are integers (so if a right triangle is Pythagorean Triple triangle), then the perimeter of the triangle must be even.

(2) If the triangle's area is doubled, the result is not an integer.

If the triangle were right angled, the area would be \(\frac{(leg_1)*(leg_2)}{2}\) and double that would be \(2*\frac{(leg_1)*(leg_2)}{2}=(leg_1)*(leg_2)=integer*integer=integer\). Since we are told that double the area of the triangle is NOT an integer, then the triangle is NOT right angled. Sufficient.

Answer: D.

Hope it's clear.

Bunuel my interpretation of your explanation is that if the pythagorean theorem cannot be validated then the triangle cannot be a right triangle- because the Pythagorean Theorem only applies to right triangles?

Yes. If a triangle is right angled , then \((side_1)^2 + (side_2)^2 = (side_3)^2\). The reverse is also true, if \((side_1)^2 + (side_2)^2 = (side_3)^2\), then a triangle is right angled.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 19 Nov 2025
Posts: 105,390
Own Kudos:
Given Kudos: 99,977
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,390
Kudos: 778,350
Kudos
Add Kudos
Bookmarks
Bookmark this Post
adityapareshshah
Bunuel
poojamathur21
Hi Bunuel,

Could you please share the solution for this? I'm very confused!

The three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?


(1) The perimeter of the triangle is an odd integer.

Given p + q + r = odd. This implies that either all three p, q and r are odd OR two of them are even and the third one is odd.

If all three p, q and r are odd, then \((side_1)^2 + (side_2)^2 = odd+odd=even\) and \((side_3)^2=odd\). Thus \((side_1)^2 + (side_2)^2 \neq (side_3)^2\). The triangle cannot be right angled.

If two of them are even and the third one is odd, then \((side_1)^2 + (side_2)^2 = even+even=even\) and \((side_3)^2=odd\) OR \((side_1)^2 + (side_2)^2 = even+odd=odd\) and \((side_3)^2=even\). In any case \((side_1)^2 + (side_2)^2 \neq (side_3)^2\). The triangle cannot be right angled.

So, we have a definite answer to the question: the triangle is NOT right angled. Sufficient.

From above we can derive that if the lengths of all three sides of a right triangle are integers (so if a right triangle is Pythagorean Triple triangle), then the perimeter of the triangle must be even.

(2) If the triangle's area is doubled, the result is not an integer.

If the triangle were right angled, the area would be \(\frac{(leg_1)*(leg_2)}{2}\) and double that would be \(2*\frac{(leg_1)*(leg_2)}{2}=(leg_1)*(leg_2)=integer*integer=integer\). Since we are told that double the area of the triangle is NOT an integer, then the triangle is NOT right angled. Sufficient.

Answer: D.

Hope it's clear.

Hi Bunuel,

Can you please explain why the triangle is NOT right angled, if the area of the triangle is not an integer?

I think this is explained. We know that the lengths of the sides of the triangle are integers. If the triangle were right angled, the area would be \(\frac{(leg_1)*(leg_2)}{2}\) and double that would be \(2*\frac{(leg_1)*(leg_2)}{2}=(leg_1)*(leg_2)=integer*integer=integer\). Since we are told that double the area of the triangle is NOT an integer, then the triangle is NOT right angled. Sufficient.
User avatar
KarishmaB
Joined: 16 Oct 2010
Last visit: 19 Nov 2025
Posts: 16,267
Own Kudos:
77,000
 [3]
Given Kudos: 482
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,267
Kudos: 77,000
 [3]
1
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
giobas
The three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?

(1) The perimeter of the triangle is an odd integer.
(2) If the triangle's area is doubled, the result is not an integer.


Please hit kudos if you liked the question :)

Responding to a pm:

A few things about primitive pythagorean triplets (not multiples of other pythagorean triplets) a, b, c where c is the hypotenuse.
1. One of a and b is odd and the other is even.
2. c is odd.

(3, 4, 5), (5, 12, 13), (8, 15, 17) etc

The non-primitive triplets are made by multiplying each member of the primitive triplet by an integer n greater than 1. Depending on whether n is odd or even, the three sides will be (Odd, Even, Odd) or (Even, Even, Even).

Given:
p, q and r are all integers.

(1) The perimeter of the triangle is an odd integer.
The perimeter of a right triangle can never be odd.
Odd + Even + Odd = Even
Even + Even + Even = Even
Hence, the perimeter will be even in all cases.

(2) If the triangle's area is doubled, the result is not an integer.
If p, q and r are the sides of a right triangle such that r is the hypotenuse (could be any of p, q, r),
Area of this triangle = (1/2)*p*q
Double of area of this triangle = p*q
This has to be an integer.
But we know that this is not an integer. In that case, this triangle cannot be a right triangle.

If it is not a right triangle, double the area will be base*altitude. The altitude would not be an integer in this case.

Answer (D)
avatar
guptalavi24
Joined: 13 Apr 2017
Last visit: 26 Sep 2017
Posts: 9
Own Kudos:
Given Kudos: 37
Location: India
Concentration: Finance, Marketing
GRE 1: Q164 V146
WE:Analyst (Computer Software)
GRE 1: Q164 V146
Posts: 9
Kudos: 22
Kudos
Add Kudos
Bookmarks
Bookmark this Post
nainy05
quantumliner
The Three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?

Two points to be known about a Right Angled Triangle

The height and the hypotenuse of Right Angled Triangle will always be Odd Integers
The Base of the Right Angled Triangle will always be an Even Integer

Statement 1) the perimeter of the triangle is an odd integer.
Based on the above, the perimeter of a Right Angled Triangle will always be Even. Hence the Triangle in question is not a right Angled Triangle. This statement is sufficient.

Statement 2) if the triangle's area is doubled, the result is not an integer.

The Area of a Right Angled Triangle is 1/2 * b*h. On doubling this it becomes b*h. Since all sides of a Right Angles Triangle are integers, b*h will also be an integer. So in this case, the Triangle in question is not a right Angled Triangle. This statement is sufficient.

Answer is D


Consider : 6,8,10... These also form right angled triangle.
So,I think reasoning for St 1 may not be correct...


6,8,10 in its simplest form will be 3,4,5.
User avatar
Madhavi1990
Joined: 15 Jan 2017
Last visit: 15 Jul 2021
Posts: 254
Own Kudos:
Given Kudos: 931
Posts: 254
Kudos: 93
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?

(1) The perimeter of the triangle is an odd integer.
(2) If the triangle's area is doubled, the result is not an integer.

Thought of pythagorean triplets first --> 3,4,5/ 12,13,5/ 8/10/6, 8/15/17 --> each of these have an even integer divisible by two, and each's perimeter is even cz in each case o + o + e is e (I did this by adding)

So Qx is asking us if triangle pqr is actually right angled or not.

St 1: triangle perimeter is odd. Based on quite a few pairs, perimeter is even. Which means, this triangle isn't a right triangle with integers. Sufficient.

St 2: If the triangle's area is doubled, the result is not an integer. --> if the double of something isn't divisible by 2 (I'm using formula 1/2 bh for area) so halfing it will also not be divisible by 2. Each pythagorean triplet right triangle has an even integer as its height, so this triangle in question isn't a right triangle. Sufficient

So answer is D.
User avatar
ravikumarmishra
Joined: 10 Aug 2009
Last visit: 11 Apr 2019
Posts: 51
Own Kudos:
Given Kudos: 89
Products:
GMAT 1: 640 Q48 V31
Posts: 51
Kudos: 18
Kudos
Add Kudos
Bookmarks
Bookmark this Post
giobas
The three sides of triangle have length p, q and r, each an integer. Is this triangle right triangle?

(1) The perimeter of the triangle is an odd integer.
(2) If the triangle's area is doubled, the result is not an integer.


Please hit kudos if you liked the question :)

Since statement 1 can be easily evaluated using pythagorean triplets. Here is another way to evaluate statement 2:

Area of triangle is \(= 1/2*p*q*sin\alpha\), where \(\alpha\) is the angle between p & q. Now if we double this area, it will become \(p*q*sin\alpha\). The only thing you need to know is that \(sin 90 = 1\) and for any other angle the value of \(sin\) is non-integer. Since doubling the area makes it non integer and p and q are already integers => \(sin \alpha\) is non integer => Hence we know that the angle between p and q is not 90. So statement 2 is sufficient.
avatar
john90alfred
Joined: 27 Sep 2018
Last visit: 25 Jan 2021
Posts: 2
Given Kudos: 2
Posts: 2
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi,i feel this question itself is wrong, as explained by Bunuel and in other answers, integer * integer has to equal an integer but Statement 2 states otherwise going against what is given in the question (that p,q, r are integers), please share your thoughts folks

Posted from my mobile device
User avatar
Basshead
Joined: 09 Jan 2020
Last visit: 07 Feb 2024
Posts: 925
Own Kudos:
Given Kudos: 432
Location: United States
Posts: 925
Kudos: 302
Kudos
Add Kudos
Bookmarks
Bookmark this Post
john90alfred
Hi,i feel this question itself is wrong, as explained by Bunuel and in other answers, integer * integer has to equal an integer but Statement 2 states otherwise going against what is given in the question (that p,q, r are integers), please share your thoughts folks

Posted from my mobile device

I agree -- the statements should not contradict each other.
User avatar
hadimadi
Joined: 26 Oct 2021
Last visit: 03 Dec 2022
Posts: 114
Own Kudos:
Given Kudos: 94
Posts: 114
Kudos: 31
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi,

(1) We either have 3 odds or 1 odd and 2 even. In a RT, we can apply the pythagorean, so let's test both cases:

Case 1, 3 odd: root(odd^2+odd^2)=root(odd+odd)=root(even)=even, but all three sides are odd, so this can't be a RT
Case 2, exactly 1 odd, subcase with hypotenuse odd: root(even^2+even^2)=root(even)=even, but the third side is supposed to be odd, so this can't be a RT
Case 2, exactly 1 odd, subcase with hypotenuse even: root(even^2+odd^2)=root(odd), but that is not even, so this can't be a RT, so not suff

(2) 2*A_Triangle=1/2*g*h=g*h=odd, with g being an integer (because it is either p,q, or r) -> h is not an integer. But for a RT, the height is always one of the sides (here p,q,r) which are all integers, so not suff

-> (D)
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,587
Own Kudos:
Posts: 38,587
Kudos: 1,079
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Moderators:
Math Expert
105390 posts
496 posts