Posted by **Punkie** on Friday, December 18, 2009 at 8:12pm.

I am to find the area of an equilateral triangle whose side is 5... I know I need to find the highth before I find the area, but I end up with a hight of the square root of 31.25, is this right? if so how do I continue and solve for the area with this kind of number?

- Math -
**bobpursley**, Friday, December 18, 2009 at 10:05pm
*

You can use Heron of Alexandria's formula

Area= sqrt(s(s-a)(s-b)(s-c))

where s is one half perimerter, and a,b,c are the sides of the triangle.

Area= sqrt(15/2 *(5/2*5/2*5/2))

area= sqrt((5/2)^4 (3))

= 25/4 sqrt 3 which is your answer.

Now your height. I get h=5sin60=5sqrt3/2= 4.33

area= 1/2 b*h= 1/2*5*4.33 which is the same as Heron's formula.

Answer this Question

## Answer This Question

## Related Questions

- Math - I am to find the area of an equilateral triangle whose side is 5... I ...
- Math - An equilateral triangle s divided into 4 congruent equilateral triangles...
- Calculus - Consider a regular tetrahedron whose face is an equilateral triangle ...
- algebra/math - I have this figure of a square QRST with an equilateral triangle ...
- geometry triangle - 1. can you tell me how to find the area of an equilateral ...
- geometry - Find the area of a circle circumscribed about an equilateral triangle...
- geometry - Theres a circle with an equilateral triangle in the middle. The ...
- math - area of a triangle is equal of the area of a square of side 60 m. Find ...
- geometry - Open that link please please help me with my assignments 1. in the ...
- Physics - An equilateral triangle initially has side length equal to 17 cm. Each...

More Related Questions