suppose a sphere cylinder and Cone eyes 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 answer

To determine the relationship between the volumes of the sphere, cylinder, and cone with the specified characteristics, we first need the volume formulas for each shape:

  1. Sphere: \[ V_{\text{sphere}} = \frac{4}{3} \pi r^3 \]

  2. Cylinder: \[ V_{\text{cylinder}} = \pi r^2 h \] Given that the height \(h\) is twice the radius \(r\), we substitute \(h = 2r\): \[ V_{\text{cylinder}} = \pi r^2 (2r) = 2 \pi r^3 \]

  3. Cone: \[ V_{\text{cone}} = \frac{1}{3} \pi r^2 h \] Again substituting \(h = 2r\): \[ V_{\text{cone}} = \frac{1}{3} \pi r^2 (2r) = \frac{2}{3} \pi r^3 \]

Now we can compare the volumes:

  • \( V_{\text{sphere}} = \frac{4}{3} \pi r^3 \)
  • \( V_{\text{cylinder}} = 2 \pi r^3 \)
  • \( V_{\text{cone}} = \frac{2}{3} \pi r^3 \)

To analyze the relationships, we can express the volumes in terms of fractions of \( V_{\text{cylinder}} \):

  1. The volume of the sphere compared to the cylinder: \[ \frac{V_{\text{sphere}}}{V_{\text{cylinder}}} = \frac{\frac{4}{3} \pi r^3}{2 \pi r^3} = \frac{4/3}{2} = \frac{4}{6} = \frac{2}{3} \] So: \[ V_{\text{sphere}} = \frac{2}{3} V_{\text{cylinder}} \]

  2. The volume of the cone compared to the cylinder: \[ \frac{V_{\text{cone}}}{V_{\text{cylinder}}} = \frac{\frac{2}{3} \pi r^3}{2 \pi r^3} = \frac{2/3}{2} = \frac{2}{6} = \frac{1}{3} \] So: \[ V_{\text{cone}} = \frac{1}{3} V_{\text{cylinder}} \]

In summary, the relationships are:

  • The volume of the sphere is \(\frac{2}{3}\) of the volume of the cylinder.
  • The volume of the cone is \(\frac{1}{3}\) of the volume of the cylinder.

Thus, the relationships can be expressed as: \[ V_{\text{sphere}} < V_{\text{cone}} < V_{\text{cylinder}} \] Specifically, in fractional form: \[ V_{\text{sphere}} = \frac{2}{3} V_{\text{cylinder}} \quad \text{and} \quad V_{\text{cone}} = \frac{1}{3} V_{\text{cylinder}} \] So the volume of the sphere is greater than the volume of the cone and less than that of the cylinder.