So I have to draw two rectangles on graph paper that each have to fit in a 15 by 20 block. The first rectangle can be what ever size you want but the second one needs be similar with a 3/5 ratio of the first. I can't figure out what their sizes should be.

Answer 1

1. Choose Length and Width of the larger rectangle that are divisible by 5.

2. The corresponding sides of the smaller rectangle should be 3/5 of the larger.

L1 = 10
W1 = 5

L2 = (3/5) * 10 = 6.
W2 = (3/5) * 5 = 3.