Question

if the area of an equilateral triangle is 81✓3cm finds its perimeter

Answer 1

Given,
Area of equilateral triangle=81√3 cm²
To find,
Its perimeter
ATQ,
Area of equilateral triangle=(√3a²)/4
81√3=(√3a²)/4
81√3/√3=a²/4
81*4=a²
324=a²
a=√324
a=18 cm

Perimeter of an equilateral triangle=3a
3*18=54 cm

Hope this helps you!

Answer 2

Hola here is your answer


We know that area of equilateral triangle = √3/4 ×(side)^2

so,

= √3/4 ×(s) ^2 = 81√3

s^2= 81√3×4/√3

√3 gets cancelled

thus,

s^2= 81×4

s^2 = 324

so,

s= √324

= 18 cm

now we know one side is 18 cm

perimeter of an equilateral triangle = sum of all sides

All sides of an equilateral triangle are equal.

thus, its perimeter = 18+18+18

= 54cm

Hope it helps!!