What makes a circle a special kind of geometric figure?

Which explanation can be used to informally derive the formula for the volume of a cone? a cylinder is exactly 3 times bigger than a cone with the same height and radius. therefore, the formula for the volume of a cone is 13 of the volume of a cylinder with the same height and radius. a cone is similar to a triangular pyramid except that a cone has curved edges. therefore, the formula for the volume of a cone can be derived by using the formula of a triangular pyramid and using the radius instead of the base length. a cone is approximately the same size as 1.5 spheres. using the formula for the volume of a sphere and multiplying it by 1.5 will give the formula for the volume of a cone. a cone consists of a circle as a base and triangles for its body. the formula for the volume of a cone can be derived by adding the formula for the area of circle and the area of the number of triangles that will cover the body of a cone.

One-third of the people from country a claim that they are from country b, and the rest admit they are from country a. one-fourth of the people from country claim that they are from country a, and the rest admit they are from country b. in a combined census of the two countries, one-half of the total claimed to be from a. what is the ratio of the populations of country a to that of country b.

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie