One triangle has side lenghts of 5 inches , 12 inches, and 13 inches. the side lengths of a second triangle are 15 inches, 36 inche, and 39 inches. what is the constant of proportianality between the two traingles?

Hello,
To find the proportional relationship:
Side length of the first triangle/ Side length of the second triangle
Apply it to this problem:
5/15
12/36
13/39
Which all equal to 1/3. As a result, the constant of proportionality between the rwp triangle is 1/3. Hope it help!