Question

The length of a side in an equilateral triangle is 5 inches. Find the area of the triangle.
5√3
6.25√3
12.5√3

Answer 1

Heron' s Formula
http://mste.illinois.edu/dildine/heron/triarea.html

\[\text{area}=\sqrt{\frac{3*5}{2}\left(\frac{3*5}{2}-5\right)^3}=\frac{25 \sqrt{3}}{4}=10.8253 \]\[6.25 \sqrt{3} \text{ from} \text{ the} \text{ problem's} \text{ solution} \text{ choices} \]