I suck at math so thanks for helping

Answer:
7.5
Step-by-step explanation:
The square has 4 equal sides, so you take the p,(30) and divide it. 30/4 = 7.5
To check your answer add 7.5 four times since the square has 4 equal sides.
7.5 + 7.5 = 15
15 + 7.5 = 22.5
22.5 + 7.5 = 30