A yield sign is an equilateral triangle, with side length of 34 inches. How many square inches of material are needed to make a sign? Round your answer to the nearest tenth of a square inch.
(Points : 2)
499.8 in2
578 in2
289 in2
705.6 in2

Question

A yield sign is an equilateral triangle, with side length of 34 inches. How many square inches of material are needed to make a sign? Round your answer to the nearest tenth of a square inch.
 (Points : 2)
       499.8 in2
       578 in2
       289 in2
       705.6 in2

anonymous · Answer

@jim_thompson5910

jim_thompson5910 · Answer

A = (1/4)*(s^2)*sqrt(3)

A = (1/4)*(34^2)*sqrt(3)

A = (1/4)*(1156)*sqrt(3)

A = ???

anonymous · Answer

thts hard

jim_thompson5910 · Answer

I'm getting 500.56268 which isn't an answer choice, but it's close to choice A

so it might be due to rounding error

anonymous · Answer

289

anonymous · Answer

look wat i found but i dnt think they giv her the answer http://openstudy.com/study#/updates/500940c5e4b020a2b3be6202

anonymous · Answer

@jim_thompson5910

jim_thompson5910 · Answer

yeah they're saying the same thing

calculusfunctions · Answer

There is more than one way to view this problem. First you know that the area of a triangle is  Area = (0.5)(base)(height).  In any equilateral triangle$$A =\frac{ \sqrt{3} }{ 2 }b ^{2}$$Since all three sides of a triangle are known, you could also apply Heron's formula for the area of a triangle, which is$$A =\sqrt{s(s -a)(s -b)(s -c)}$$where  s  is half of the perimeter of the triangle and  a,  b,  and  c are the side lengths.

calculusfunctions · Answer

Sorry, that should be$$A =\frac{ \sqrt{3} }{ 4 }b ^{2}$$