Question

Find the area of an equilateral triangle having perimeter of 18cm.

Answer 1

Find side length

`"Side" = "Perimeter"/3 = 18/3 = 6  cm`

`"Area" = sqrt3/4 xx a^2`

a = side length.

`Area = sqrt3/4 xx (6^2) = sqrt3/4 xx 36 = 9sqrt3  cm^2`

`9sqrt3 = 9 xx 1.732 = 15.588  cm^2`

`Area = 9sqrt3  cm^2 = 15.6  cm^2`