The missing side length can be 15 units or -15 units. Since the length of a side cannot be negative, the missing side length is 15 units.
Steps to solve:
1. Substitute the given values into the Pythagorean theorem:
2. Simplify the equation:
225 = x^2
3. Take the square root of both sides:
x = ±√225
4. Evaluate the square root:
x = 15, -15
The missing side length can be 15 units or -15 units. Since the length of a side cannot be negative, the missing side length is 15 units.