Respuesta :

Answer:

21 feet

Explanation:

Using pythagorean theorem to find the length of the added length of the bottom.

A^2+B^2=C^2 or 4^2+B^2=5^2 or 16+B^2=25

25-16=9 so B^2 is 9 and the square root of that is 3 so B is 3. Then you add 15+3+3 to get 21.