Solve
-A Balloon Is Secured to Rope That Is Staked $10 \sqrt { 41 } \mathrm { ft }$

Solve.
-A balloon is secured to rope that is staked to the ground. A breeze blows the balloon so that the rope is taut while the balloon is directly above a flag pole that is 40 feet from where the rope is staked down. Find the altitude of the balloon if the rope is 50 feet long.

A) $10 \sqrt { 41 } \mathrm { ft }$
B) $3 \sqrt { 10 } \mathrm { ft }$
C) $\sqrt { 10 } \mathrm { ft }$
D) $30 \mathrm { ft }$