Answer:
z = 7.5
Explanation:
Polygon ABCD and polygon EFGH are similar, therefore, their sides would be proportional to each other. This means the ratio of their corresponding sides would be equal to each other.
BC corresponds to FG
CD corresponds to GH
Therefore:
8/6 = 10/z
4/3 = 10/z
Cross multiply
4*z = 10*3
4z = 30
4z/4 = 30/4
z = 7.5