Question

if the area of equilateral triangle is 81√3 cm find its perimeter​

Answer 1

Answer:

Step-by-step explanation:

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.

Answer 2

Answer:  54cm

Step-by-step explanation:

Thus , area of an equilateral triangle = $\sqrt{3}*a^{2} /4$ = 81√3cm

a = length of each side of the equilateral triangle

a²/4 =  81√3  / √3 = 81

a² = 81*4 = 324

a = √256 = 18

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