Solve the Problem $21 \mathrm{ft}$ Long the Ladder Leading to the Slide Is

Multiple Choice

Solve the problem.
-Below is a diagram of a water slide. The slide is $21 \mathrm{ft}$ long. The ladder leading to the slide is $15 \mathrm{ft}$ long. How far is it from the end of the slide to the foot of the ladder? Round approximations to the nearest tenth.

A) $18 \mathrm{ft}$
B) $108 \mathrm{ft}$
C) $7.4 \mathrm{ft}$
D) $14.7 \mathrm{ft}$