Suppose a sphere, cylinder, and cone all share the same radius and the cylinder and cone also share the same height, which is twice the radius. Which of the following is true about the relationship between the volume formulas for the sphere, cylinder, and cone?(1 point)

PICK ONE

Responses

3 cones = 1 cylinder
3 cones = 1 cylinder

sphere = cylinder + cone
sphere = cylinder + cone

sphere - cone = cylinder
sphere - cone = cylinder

1 cylinder = 2 cones + 1 sphere

1 answer

To analyze the volumes of the sphere, cylinder, and cone, we can use their volume formulas and the given information about their dimensions.

  1. Volume of the sphere (V_s): \[ V_s = \frac{4}{3} \pi r^3 \]

  2. Volume of the cylinder (V_c): Given the height (h) of the cylinder is twice the radius (h = 2r): \[ V_c = \pi r^2 h = \pi r^2 (2r) = 2\pi r^3 \]

  3. Volume of the cone (V_co): The height of the cone is also 2r: \[ V_co = \frac{1}{3} \pi r^2 h = \frac{1}{3} \pi r^2 (2r) = \frac{2}{3} \pi r^3 \]

Now, let's look at the relationships:

  • 3 cones: \[ 3 \times V_co = 3 \times \frac{2}{3} \pi r^3 = 2\pi r^3 = V_c \] This means 3 cones = 1 cylinder.

  • Sphere in terms of cylinder and cone: \[ V_s = \frac{4}{3} \pi r^3 = V_c - V_co = 2\pi r^3 - \frac{2}{3} \pi r^3 = \frac{6}{3} \pi r^3 - \frac{2}{3} \pi r^3 = \frac{4}{3} \pi r^3 \] This means sphere = cylinder - cone.

  • Sphere minus cone: \[ V_s - V_co = \frac{4}{3} \pi r^3 - \frac{2}{3} \pi r^3 = \frac{2}{3} \pi r^3 \] This is equal to \(\frac{1}{3} V_c\), not equal to the cylinder's volume.

  • 1 cylinder and cones and sphere: \[ V_c = 3 V_co + V_s = 2\pi r^3 \] This doesn't hold as well.

Thus, the relationship that is true is:

3 cones = 1 cylinder.