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# Two sides of a triangle have length 6 and 8. Which of the following ar

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Two sides of a triangle have length 6 and 8. Which of the following ar  [#permalink]

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25 Feb 2015, 03:20
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Two sides of a triangle have length 6 and 8. Which of the following are possible areas of the triangle?

I. 2
II. 12
III. 24

A. I only
B. I and II only
C. II and III only
D. I and III only
E. I, II, and III

Kudos for a correct solution.

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Re: Two sides of a triangle have length 6 and 8. Which of the following ar  [#permalink]

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25 Feb 2015, 22:44
5
9
Hi All,

When you're given the lengths of two sides of a triangle, you have no way of knowing what type of triangle you're dealing with. It MIGHT be a right triangle. It MIGHT be isosceles. It MIGHT be a really long, thin triangle that's ALMOST a straight line (but still has 3 distinct sides).

As such, you have to find the maximum value for the area; with that, you know that every SMALLER area is also possible. In this type of situation, the maximum area will occur if the two sides form the legs of a right triangle. With these side lengths (6 and 8), we'd have...

Area = (1/2)(6)(8) = 24 = maximum possible area

Now we know that the range of possible areas is 0 < Area <= 24.

So all three values are possible.

GMAT assassins aren't born, they're made,
Rich
_________________
760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

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# Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save $75 + GMAT Club Tests Free Official GMAT Exam Packs + 70 Pt. Improvement Guarantee www.empowergmat.com/ ##### General Discussion Intern Joined: 19 Jan 2014 Posts: 23 GMAT 1: 730 Q50 V39 WE: Accounting (Accounting) Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 25 Feb 2015, 05:50 I. 2 IMHO this area is impossible, because if this would be possible than the height to the largest side with length of 8 would have to be 2*2/8 = 1/2 Third side would be larger than 2 (because of sides 6 and 8), and i think the height to the largest side will be larger than 1/2 III. 24 This area is possible, 6*8*1/2 = 24 II. 12 Upon analysing answer options without I and with III option there is only one answer: C Answer is C, II and III are possible areas p.s. solved very quickly, in less than 20 sec Math Expert Joined: 02 Aug 2009 Posts: 7743 Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 25 Feb 2015, 07:03 1 Plastelin wrote: I. 2 IMHO this area is impossible, because if this would be possible than the height to the largest side with length of 8 would have to be 2*2/8 = 1/2 Third side would be larger than 2 (because of sides 6 and 8), and i think the height to the largest side will be larger than 1/2 III. 24 This area is possible, 6*8*1/2 = 24 II. 12 Upon analysing answer options without I and with III option there is only one answer: C Answer is C, II and III are possible areas p.s. solved very quickly, in less than 20 sec hi why cant be the height be less than 2... yes the third side has to be more than>2,otherwise it will become a straight line... say the side is just above 2.. then the height can be .1,.2,1/3,1/4 etc so we have base 8 and height 1/8... area =1/2*1/8*8=1/2 .. so 2 is possible _________________ Math Expert Joined: 02 Aug 2009 Posts: 7743 Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 25 Feb 2015, 07:07 3 Bunuel wrote: Two sides of a triangle have length 6 and 8. Which of the following are possible areas of the triangle? I. 2 II. 12 III. 24 A. I only B. I and II only C. II and III only D. I and III only E. I, II, and III Kudos for a correct solution. hi, lets see the minimum value and max value.. 1)min value... two sides are 6,8.. third side has to be more than 2, otherwise we will have a straight line... with height slightly above 2, we can have height as 1/10,1/8,1/2 etc.. so min value can be any positive number, fraction decimal etc... 2) max valve .. lets take these as two sides of a right angle triangle, then area=1/2*8*6=24.. all three values fit in so ans E.. _________________ SVP Status: The Best Or Nothing Joined: 27 Dec 2012 Posts: 1796 Location: India Concentration: General Management, Technology WE: Information Technology (Computer Software) Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 27 Feb 2015, 02:18 1 Answer = E. I, II, and III With dimensions of only 2 sides given (for a triangle), this becomes an open ended question Any area is possible out of the three _________________ Kindly press "+1 Kudos" to appreciate Math Expert Joined: 02 Aug 2009 Posts: 7743 Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 27 Feb 2015, 02:25 PareshGmat wrote: Answer = E. I, II, and III With dimensions of only 2 sides given (for a triangle), this becomes an open ended question Any area is possible out of the three hi paresh, there is a limitation on the upper end of area, which is area of a right angle triangle with these two sides.. _________________ SVP Status: The Best Or Nothing Joined: 27 Dec 2012 Posts: 1796 Location: India Concentration: General Management, Technology WE: Information Technology (Computer Software) Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 27 Feb 2015, 02:47 2 chetan2u wrote: PareshGmat wrote: Answer = E. I, II, and III With dimensions of only 2 sides given (for a triangle), this becomes an open ended question Any area is possible out of the three hi paresh, there is a limitation on the upper end of area, which is area of a right angle triangle with these two sides.. Fully agree Chetan... that's why mentioned out of the three given Area is maximum when height is maximum Height is maximum when its a right triangle Attachment: angle.png [ 4.18 KiB | Viewed 26078 times ] _________________ Kindly press "+1 Kudos" to appreciate Math Expert Joined: 02 Sep 2009 Posts: 55626 Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 02 Mar 2015, 05:41 1 3 Bunuel wrote: Two sides of a triangle have length 6 and 8. Which of the following are possible areas of the triangle? I. 2 II. 12 III. 24 A. I only B. I and II only C. II and III only D. I and III only E. I, II, and III Kudos for a correct solution. MAGOOSH OFFICIAL SOLUTION: This requires a picture explanation. Consider the leg of 6 and the leg of 8 attached at a "hinged" joint at B. Attachment: originals.jpg [ 15.57 KiB | Viewed 25994 times ] Here, the angle is made very narrow, only 1/100 of a degree. The area of this triangle would be 0.00419 --- you don't need to be able to calculate something like this for the test. The point is -- if the angle were one millionth, or one billionth, the area could be really really small --- greater than zero, but a really tiny decimal. So, clearly, the area can be less than two. Here, I moved the legs of 6 and 8 apart a little, and produced a triangle with an area of exactly two: Attachment: originals (1).jpg [ 19.59 KiB | Viewed 26014 times ] Again, you don't have to know how to build a triangle like this: this is just to show you that it is, indeed possible. As we increase the angle, we get triangles with more and more area. You do not need to know how to find these areas --- this is just to demonstrate that the area would increase. Attachment: originals (2).jpg [ 21.71 KiB | Viewed 26008 times ] Attachment: originals (3).jpg [ 22.77 KiB | Viewed 26024 times ] Attachment: originals (4).jpg [ 22.5 KiB | Viewed 25983 times ] Now, there's a geometry theorem that states, when the angle is 90°, the area of the triangle will be a maximum. At that point, the length of 8 will be the base, and the length of 6 will be the height, so the area = 0.5*bh = 24, the maximum possible area. Thus, the triangle can have all three areas: I, II, and III. Answer = E. _________________ Math Expert Joined: 02 Sep 2009 Posts: 55626 Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 02 Mar 2015, 05:42 Bunuel wrote: Two sides of a triangle have length 6 and 8. Which of the following are possible areas of the triangle? I. 2 II. 12 III. 24 A. I only B. I and II only C. II and III only D. I and III only E. I, II, and III Kudos for a correct solution. Similar questions to practice: if-two-sides-of-a-triangle-are-12-and-8-which-of-the-141227.html if-two-sides-of-a-triangle-have-lengths-2-and-5-which-of-th-163409.html _________________ LBS Thread Master Joined: 13 Jan 2015 Posts: 97 Location: United Kingdom Concentration: Other, General Management Schools: LBS '19 (WL) GMAT 1: 690 Q48 V36 Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 26 Mar 2015, 08:41 Hi Rich, Going with your logic on the areas, and looking at this example- if-two-sides-of-a-triangle-are-12-and-8-which-of-the-141227.html Why cant we find possible outcomes for the third leg and then try and see if we get an area Eg, from the link, let third side be x then 12-8<x<20 so if we assume x to be 16,, and assume the triangle is a right triangle with 12 as the height, Then we can have an area of 1/2*12*16 = 64, therefore the area can be more than 56 Any thoughts?? EMPOWERgmat Instructor Status: GMAT Assassin/Co-Founder Affiliations: EMPOWERgmat Joined: 19 Dec 2014 Posts: 14343 Location: United States (CA) GMAT 1: 800 Q51 V49 GRE 1: Q170 V170 Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 26 Mar 2015, 11:24 Hi Tmoni26, You can actually catch the error in this logic yourself. Try drawing the triangle that you describe. What are the 3 sides (and how does this NOT match up with the information in the prompt)? GMAT assassins aren't born, they're made, Rich _________________ 760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com *****Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***** # Rich Cohen Co-Founder & GMAT Assassin Special Offer: Save$75 + GMAT Club Tests Free
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Re: Two sides of a triangle have length 6 and 8. Which of the following ar  [#permalink]

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15 Jul 2015, 06:44
PareshGmat wrote:
Answer = E. I, II, and III

With dimensions of only 2 sides given (for a triangle), this becomes an open ended question

Any area is possible out of the three

Well, there is another way to solve such questions using trignometry. Area of a triangle is $$1/2absin$$($$\alpha$$), where $$a$$ and $$b$$ are any two sides of the triangle and $$\alpha$$ is the angle contained by these two sides. Now area is maximum when sine function becomes $$1$$ at $$\alpha$$ $$=$$$$90^{\circ}$$. Also area tends to $$0$$ as $$\alpha$$ approaches $$0^{\circ}$$.
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 14343
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: Two sides of a triangle have length 6 and 8. Which of the following ar  [#permalink]

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15 Jul 2015, 13:24
Hi ravindra88,

You're going to find that most GMAT questions can be solved in a variety of ways, so you should look for whichever method is easiest/fastest for you. It is worth noting, however, that Trigonometry is NOT tested on the GMAT, so choosing to use such an approach is up to you (but is not expected of you).

GMAT assassins aren't born, they're made,
Rich
_________________
760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

*****Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!*****

# Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save $75 + GMAT Club Tests Free Official GMAT Exam Packs + 70 Pt. Improvement Guarantee www.empowergmat.com/ Board of Directors Joined: 17 Jul 2014 Posts: 2548 Location: United States (IL) Concentration: Finance, Economics GMAT 1: 650 Q49 V30 GPA: 3.92 WE: General Management (Transportation) Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 08 Jan 2016, 19:49 2 ways to solve it: 1 - plug in numbers: h=1/2. 1/2*8 /2 = 2. 1 yes. h=1. 1*8/2 = 4. 2 yes. h=6. 6*8/2 = 24. 3 yes. other method: third side must be greater than 2, less than 14. greatest possible area thus can be almost 14*8/2 or slightly less than 56. everything below - is possible, so long as it is not 0 or negative. Manager Joined: 06 Jun 2013 Posts: 155 Location: India Concentration: Finance, Economics Schools: Tuck GMAT 1: 640 Q49 V30 GPA: 3.6 WE: Engineering (Computer Software) Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 02 Jul 2017, 00:29 24 is the one possibility if it is a right angled triangle. once we get this, the only thing we need to do is to change the angle between the two given sides and thus changing the height before it becomes 0 degree or 180 degree (both excluded). so area can be anything based on the height of the triangle. Director Joined: 02 Sep 2016 Posts: 657 Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 06 Jul 2017, 22:24 I did it this way. Area= 0.5 *base*height We have no clue about the third side. It may not be an integer. We just know that: 2<third side<14 But there are so many values that c can take even in this range. Let's work with the options: 1) Area= 2= 0.5 *b*h b*h= 4 2) b*h= 24 3) b*h= 48 There are many possible values that can result in these products. So I selected all three. Does this make sense? _________________ Help me make my explanation better by providing a logical feedback. If you liked the post, HIT KUDOS !! Don't quit.............Do it. Intern Joined: 09 Dec 2013 Posts: 27 Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags Updated on: 11 Feb 2018, 20:31 Shiv2016 wrote: I did it this way. Area= 0.5 *base*height We have no clue about the third side. It may not be an integer. We just know that: 2<third side<14 But there are so many values that c can take even in this range. Let's work with the options: 1) Area= 2= 0.5 *b*h b*h= 4 2) b*h= 24 3) b*h= 48 There are many possible values that can result in these products. So I selected all three. Does this make sense? Thanks RIch Originally posted by Buttercup3 on 13 Jul 2017, 21:41. Last edited by Buttercup3 on 11 Feb 2018, 20:31, edited 1 time in total. EMPOWERgmat Instructor Status: GMAT Assassin/Co-Founder Affiliations: EMPOWERgmat Joined: 19 Dec 2014 Posts: 14343 Location: United States (CA) GMAT 1: 800 Q51 V49 GRE 1: Q170 V170 Re: Two sides of a triangle have length 6 and 8. Which of the following ar [#permalink] ### Show Tags 14 Jul 2017, 07:28 1 Hi Buttercup3, The answer to your question can be found in a number of posts earlier on in the thread. Here's one of them: When you're given the lengths of two sides of a triangle, you have no way of knowing what type of triangle you're dealing with. It MIGHT be a right triangle. It MIGHT be isosceles. It MIGHT be a really long, thin triangle that's ALMOST a straight line (but still has 3 distinct sides). As such, you have to find the maximum value for the area; with that, you know that every SMALLER area is also possible. In this type of situation, the maximum area will occur if the two sides form the legs of a right triangle. With these side lengths (6 and 8), we'd have... Area = (1/2)(6)(8) = 24 = maximum possible area Now we know that the range of possible areas is 0 < Area <= 24. So all three areas (including "2") are possible. GMAT assassins aren't born, they're made, Rich _________________ 760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com *****Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***** # Rich Cohen Co-Founder & GMAT Assassin Special Offer: Save$75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/
Intern
Joined: 09 Dec 2013
Posts: 27
Re: Two sides of a triangle have length 6 and 8. Which of the following ar  [#permalink]

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14 Jul 2017, 09:29
EMPOWERgmatRichC wrote:
Hi Buttercup3,

The answer to your question can be found in a number of posts earlier on in the thread. Here's one of them:

When you're given the lengths of two sides of a triangle, you have no way of knowing what type of triangle you're dealing with. It MIGHT be a right triangle. It MIGHT be isosceles. It MIGHT be a really long, thin triangle that's ALMOST a straight line (but still has 3 distinct sides).

As such, you have to find the maximum value for the area; with that, you know that every SMALLER area is also possible. In this type of situation, the maximum area will occur if the two sides form the legs of a right triangle. With these side lengths (6 and 8), we'd have...

Area = (1/2)(6)(8) = 24 = maximum possible area

Now we know that the range of possible areas is 0 < Area <= 24.

So all three areas (including "2") are possible.

GMAT assassins aren't born, they're made,
Rich

Thank You Sir for the reply
Re: Two sides of a triangle have length 6 and 8. Which of the following ar   [#permalink] 14 Jul 2017, 09:29

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