GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 17 Jun 2019, 08:03 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

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.  Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD

Author Message
TAGS:

Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 55635
Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD  [#permalink]

Show Tags 00:00

Difficulty:   45% (medium)

Question Stats: 75% (01:49) correct 25% (01:48) wrong based on 133 sessions

HideShow timer Statistics Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD equal to 30 degrees.

(1) One side of Triangle ABD is equal to 2.

(2) One side of Rectangle ABCD is 1.

Attachment: img_3862.png [ 4.97 KiB | Viewed 3563 times ]

_________________
Director  D
Joined: 05 Mar 2015
Posts: 992
Re: Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD  [#permalink]

Show Tags

2
Bunuel wrote: Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD equal to 30 degrees.

(1) One side of Triangle ABD is equal to 2.

(2) One side of Rectangle ABCD is 1.

Attachment:
The attachment img_3862.png is no longer available

Combined statements are also not sufficient
Consider below attached images
where Case 1 is unknown triangle & case 2 is 30-60-90 triangle
Hence insuff

Ans E
Attachments img_386.png [ 11.19 KiB | Viewed 2931 times ]

Director  S
Joined: 12 Nov 2016
Posts: 715
Location: United States
Schools: Yale '18
GMAT 1: 650 Q43 V37 GRE 1: Q157 V158 GPA: 2.66
Re: Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD  [#permalink]

Show Tags

Okay so I made an educated guess and got this question right- but kudos for feedback in my reasoning because I don't want to choke or second guess myself on test day.

Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD equal to 30 degrees.

(1) One side of Triangle ABD is equal to 2.

(2) One side of Rectangle ABCD is 1.

Statement (1) tells us that one side of triangle ABD is equal to 2- well, which side is that? Is it the side that corresponds to one of the two 90 degree angles in the rectangle. Also, we cannot just assume that the two triangles are 45 45 for the sake of not falling into GMAT DS traps. If that were true then, that is if mathematically the question and diagram in itself validated a 45 45 90 triangle, then the purpose of the question is defeated- in other words, the whole point of this question is to establish whether or not we have enough information to conclude angle ABD is equal to 30; therefore, nothing in the question or diagram itself can solve that question. The information needed to solve the question, or lack of it, is derived from the two statements.

Statement (2) tells us one side of the rectangle is 1- which side is that though? And how can we compute the length of the other side with this data. If we could do that then maybe we could extrapolate ratios through degrees based on the side lengths but the side lengths have no limitation (etc. you could have two sides of 1 and two sides of 3, or two sides of 1 and two sides of 2). Hence, this statement is insufficient.

If we combine both of these statements, we still do not have enough information- we cannot just use the Pythagorean theorem to find the hypotenuse length and derive a conclusion about the angles of the triangle by squaring 1 and 2. This is my best guest/ reasoning.
Intern  B
Joined: 03 Dec 2016
Posts: 33
Re: Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD  [#permalink]

Show Tags

Bunuel wrote:
Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD equal to 30 degrees.

(1) One side of Triangle ABD is equal to 2.

(2) One side of Rectangle ABCD is 1.

Attachment:
img_3862.png

Hi,

I had a very basic doubt here.

If a line divides a rectangle into two equal triangles, shouldn't this line be the rectangle's diagonal and create a 45 degree angle at the vertices?

Thanks,
Novice
Math Expert V
Joined: 02 Sep 2009
Posts: 55635
Re: Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD  [#permalink]

Show Tags

1
Novice90 wrote:
Bunuel wrote:
Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD equal to 30 degrees.

(1) One side of Triangle ABD is equal to 2.

(2) One side of Rectangle ABCD is 1.

Attachment:
img_3862.png

Hi,

I had a very basic doubt here.

If a line divides a rectangle into two equal triangles, shouldn't this line be the rectangle's diagonal and create a 45 degree angle at the vertices?

Thanks,
Novice

A diagonal in a rectangle makes 45 degree angle at the sides only when a rectangle is a square. In all other cases the angles can be anything ranging from 0 to 90, not inclusive obviously.
_________________
Intern  B
Joined: 19 Aug 2012
Posts: 1
Re: Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD  [#permalink]

Show Tags

Question: Is Angle ABD equal to 30 degrees?

After combining both 1) and 2), we see that it does not follows triangle 30-60-90 pattern.
Will there be a flaw to deduce that Angle ABD is not equal to 30 degree. Hence answering question.

Can the answer be option C (both statement together sufficient to answer). Re: Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD   [#permalink] 13 Sep 2018, 09:00
Display posts from previous: Sort by

Line DB divides Rectangle ABCD into two equal triangles. Is Angle ABD  