Answer:
Explanation:
Because of the Pythagorean Theorem, which states that a^2 + b^2 =c^2, we can find the missing side length:
1. 21^2 = 441
72^2 = 5184
2. 441 + 5184 = 5625
3. Since the question is asking for c (the missing side length), not c^2, we square root 5625:
√5625 = 75
Therefore, the missing side length is 75.
* "^" is used to represent a power/exponent.