Answer: 30 cm
Step-by-step explanation: Take note that ^2 means to the second power.
a^2 + b^2 = c^2 (hypotenuse)
18^2 + 24^2 = c^2
324 + 576 = c^2
900 = c^2
To find the length of c you have to find teh square root of 900.
√c^2 = √900
c = 30
The length of the hypotenuse is 30 cm!
Hope this helped!