Question

the area of an equilateral triangle is 81 root 3 cm square find its perimeter by using heron's formula

Answer 1

hai
in this question the triangle is equilateral triangle so, there is no need of heron's formula

Given that
we know that area is √3/4 a²
area of the equilateral triangle = 81√3
√3/4 a² = 81√3
1/4 a² = 81
a² = 81(4)
a² = 324
a = 18cm

then the perimeter of the equilateral triangle = 3×a
= 3×18
=54cm.
hope u can understand...