Question

Find the

to two decimal places.
if the area of an equilateral triangle is 81 v3 cm?, find its perimeter
​

Answer 1

54 cm

Explanation:

The area (A) of an equilateral triangle is

A =
`(s^2√(3) )/(4)` ( s is the side length ) then

`(s^2√(3) )/(4)` = 81
`√(3)` ( multiply both sides by 4 to clear the fraction )

s²
`√(3)` = 324
`√(3)` ( divide both sides by
`√(3)` )

s² = 324 ( take the square root of both sides )

s =
`√(324)` = 18

Thus

perimeter = 3 × 18 = 54 cm