Answer: 24
Step-by-step explanation: you use the formula: a^2 + b^2 = c^2. If you drew a picture, it would form a triangle with 30 as the length of the hypotonuse, and 18 as one of the legs. This given, we would have a^2 + 18^2 = 30^2 (hypotonuse = c) Then, solve.