Question

What is the area of an equilateral triangle with a perimeter of 21 inches?

Answer 1

`(49sqrt3)/4`

Explanation:

Let side length be `a` inches.

Then `3a=21" "rArr" "a=7`

Area of an equilateral triangle is given by

`" "(sqrt3a^2)/4`

`rArr" "(sqrt3xx7^2)/4=(49sqrt3)/4`