Gmatprep2- geometry

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Gmatprep2- geometry

by bkobilov » Sun Oct 03, 2010 10:30 am
Hi guys. Faced this question in gmatprep2. How to solve this question?

Given equiteral triangle with side t and square with side s. If the areas of these are equal what is the ratio of t : s?

2:3
16:3
4:3^(1/2)
2:3^(1/4)
4:3^(1/4)
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by narik11 » Sun Oct 03, 2010 11:57 am
bkobilov wrote:Hi guys. Faced this question in gmatprep2. How to solve this question?

Given equiteral triangle with side t and square with side s. If the areas of these are equal what is the ratio of t : s?

2:3
16:3
4:3^(1/2)
2:3^(1/4)
4:3^(1/4)
Given that (3^1/2*t^2)/4=s^2

t^2/s^2= 4/(3^1/2)

t/s= 2/(3^1/4)
So option D

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by GMATGuruNY » Sun Oct 03, 2010 3:54 pm
bkobilov wrote:Hi guys. Faced this question in gmatprep2. How to solve this question?

Given equilateral triangle with side t and square with side s. If the areas of these are equal what is the ratio of t : s?

2:3
16:3
4:3^(1/2)
2:3^(1/4)
4:3^(1/4)
This question is much easier if you've memorized the following:

Area of equilateral triangle = (1/4)(b^2)√3

Now let's plug in:
Let t = b = 2.
Then area of triangle = (1/4)(2^2)√3 = √3.
So area of square = √3
s^2 = √3
s = 3^(1/4)
So t:s = 2:3^(1/4)

The correct answer is D.
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