This was in response to a quiestion in the MGMAT Q Bank.. I

Question

This was in response to a quiestion in the MGMAT Q Bank..
I was able to calculate the height..
How do I calculate area of equilaterial triangle once given the height?

Jim

ggarr · Answer

A=b(h)/2 or you can use the area formula for equilateral triangles:

s^2*((sqrt)3)/(4)

jamesrwrightiii · Answer

Oops I should have been clearer
How do I calculate a side once given a height!
Sorry tired

ggarr · Answer

are we told anything else about the triangle other than its height and it being equilateral?

jamesrwrightiii · Answer

Actually no..I wish I could post the problem but it's copyrighted by MGMAT..basically it asked you to calculate a line..then they said the length of the line was the height of an equilateral triangle and then asked you to find the area..

Whatever · Answer

equilateral triangle = 2 triangles 30-60-90 which have the sides 1, sqrt3, 2 where sqrt3 = height

ggarr · Answer

yep. there you go. forgot all about that. there's your answer!

jamesrwrightiii · Answer

Ok so let me clear this up..

The height is 13..the height is opposite the 60 degree angle
The side opposite the 30 degree angle is 13/sqrt 3?

To get the area...I multiply 13 *13/ Sqrt 3?

Then take that answer *2 to account for the other "side" of the equilateral?

ggarr · Answer

13(sqrt)3 is the base of the 30-60-90 triangle. I'd multiply that by 2 and get the base of the entire equilateral triangle. then use the triangle area formula to solve:

 b (h)/2 =  26((sqrt)6) *13/2

jamesrwrightiii · Answer

So the base is 26/sqrt 3

That times height (26/sqrt3)*13/2

I think what you can do is halve the 26 to account for dividing by 2 so you can..

13*13/sqrt 3=169/sqrt 3


That isn't one of the answers:(

Whatever · Answer

Could you then post the whole Q please, may be there are some restrictions?

ggarr · Answer

Is 169((sqrt)6) one of the answers?

GMATBLACKBELT · Answer

Which MGMAT question is this? Must be from the GEO Q bank right?

jamesrwrightiii · Answer

Yep from the Geometry Q Bank...I didn't finish the bank yet so I can't get the official explanation..I got 4-5 questions in and I got tired..

This was in response to a quiestion in the MGMAT Q Bank.. I

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