The length of the base of an isosceles triangle is one forth the length of one of its legs. if the perimeter of the triangle is 25 inches, what is the length of the base? a) 5 11/16 in b) 2 7/9 in c) 4 1/6 in d) 11 1/9 in

Isosceles triangle is a triangle with 2 sides that are equal and one side that may be different in length to the other 2.
I would presume the legs refer to the 2 sides of the triangle which are equal to each other.

First, divide the sides into countable units:
Let x be a unit measure,
Let x = the base length (aka. the length that is different for the other 2 sides)
Since the base length is one fourth (I.e. 1/4) of one of the other (equal) sides, the other side will be 4x.
Since the 2 sides are the same length, the 3rd side will be 4x as well.

Add all 3 sides together, you'll get the perimeter, 4x + 4x + x = 25 <all in inches>
=> 9x = 25
=> x = 25/9
= 2 7/9 inches

Hope this helps!