Answer:
Option 3, 18.0
Explanation:
To find the Hypotenuse of a right triangle, use the Pythagoras theorem:
(see image below)
(the longest side of any right △ is always C)
In this equation, we know A is 10 and B is 15, so plug in these numbers and solve for C
Now that the equation is simplified, we find the square root of 325 to solve for C.
The final answer is C = 18.0
Hope this helps you understand :)