The russian ruble coin has a radius of 10.25 mm. what is the circumference in terms of pi ?

the answer is 20.5 pi

In angle pqr find the measure of

Worth 30 points! in this diagram, both polygons are regular. what is the value, in degrees, of the sum of the measures of angles abc and abd?

Apyramid fits exactly inside a cube. the cube and the pyramid share the same square base, and they are both exactly the same height. the volume of the cube is 66 cubic inches. what is the volume of the pyramid? explain your answer. answer asap