Would anyone know the correct answers to these three math questions?

What is the sum of the measures of the interior angles of a 21-gon?

What is the measure of an exterior angle of a regular pentagon?

c) Determine which of the following could be the side measures of a right triangle. Select all that apply.


5 ft, 4 ft, 3 ft

6 ft, 4 ft, 2 ft

11 ft, 10 ft, 6 ft