Quilt squares are cut on the diagonal to form triangular quilt pieces. the hypotenuse of the resulting triangles is 18 inches long. what is the side length of each piece?

There are several information's already given in the question. Based on those given information's the answer can be easily deduced.

Length of the hypotenuse of the triangle = 18 inches
let us assume the length of the other 2 sides = x
The
x√2 = 18
x = 18/√2
   = 18/1.414
   = 12.73 inches.
I hope that this is the answer that you were looking for and the answer has come to your desired help. 

Bis your answer. it only holds the decimal numerals