Answer:
Width of the rectangle is 15cm
Explanation:
If 64 is the perimeter and 17 is one side of the rectangle, then the opposite side must be 17 too, that leaves two sides. 64-17-17= 30. 30 divided by 2 = 15. 15+15+17+17=64 which is the perimeter, so you know your answer of 15 is correct.