Answer:
15.8
Explanation:
To complete this question, you must know the Pythagoream Theorum, which is a^2 + b^2 = c^2. Side c is the hypotenuse or the diagonal side and a and b are the other sides. So, for this problem, plug in 5 for a and 15 for b. So square 5 and add that number to the square of 15. You should get 250. But, remember that 250 is equal to C^2, not c by itself. So take the square root of 250 which would leave you with 15.8 as your side c.