PLS HELP What is the length, in feet, of AD in the isosceles trapezoid ABCD?
15 ft
c
1410
5 ft
A
D
F
Note: Figure is not drawn to scale.
O 3 feet
O 10 feet
O 141 feet
O 21 feet

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.