Answer:
m = 5
Explanation:
We are told that the two triangles are similar. Thus, each side of the larger triangle is the same multiple of the corresponding side in the smaller triangle.
Thus, 12 = k(7.2), where k is the constant of proportionality.
Solving this for k, we get
k = 12/7.2 = 1 2/3
Thus, side m is 1 2/3 times 3, or 5/3 times 3, or just 5.
m = 5