The sun casts a shadow from a flagpole. The height of the flagpole is three times the length of its shadow. The distance between the end of the shadow and the top of the flagpole is 21 feet. Find the length of the shadow and the length of the flagpole. Round to the nearest tenth of a foot.

Use the Pythagorean Theorem: In any right triangle, where \(a\) and \(b\) are the lengths of the legs and \(c\) is the length of the hypotenuse, as shown in the given figure, \(a^{2}+b^{2}=c^{2}\).

C b