Answer:
279 patches can be made.
Step-by-step explanation:
Evaluate the total area of the rectangular piece of fabric, therefore:
Area= l*w = 15*9=135
There are 31 pieces, so the total area is 135* 31 =4,185 square centimeters.
Evaluate the number of triangles that can be made dividing the total area by the area of 1 triangular piece, therefore:
n= 4,185/15=279
So the answer is 279 triangles can be made.