Question

explain how to find the length of each side of a triangle with sides of equal length, and a perimeter of 27 inches

Answer 1

They have equal lengths (all the three sides of the triangle!)
Let the length of each side be 'a'

Now, its perimeter = Sum of all the three sides

So, Perimeter= a + a + a
27 = 3a
a = 27/3 = 9

So, you have a triangle having 9 in as length of each side !

Answer 2

You have to divide 27 by three and get 9inches.