The cross-sectional areas of a right triangular prism and a right cylinder are congruent. The right triangular prism has a height of 2 units, and the right cylinder has a height of 6 units. Which conclusion can be made from the given information?

The volume of the triangular prism is half the volume of the cylinder.
The volume of the triangular prism is not equal to the volume of the cylinder.
The volume of the triangular prism is twice the volume of the cylinder.
The volume of the triangular prism is equal to the volume of the cylinder.

1 answer

To compare the volumes of the right triangular prism and the right cylinder, let's start with the formulas for their volumes.

  1. The volume \( V \) of a right triangular prism is given by: \[ V_{\text{prism}} = \text{Area of base} \times \text{Height} \] Let \( A \) be the area of the triangular base. Thus, \[ V_{\text{prism}} = A \times 2 \]

  2. The volume \( V \) of a right cylinder is given by: \[ V_{\text{cylinder}} = \text{Area of base} \times \text{Height} \] The base area is also \( A \) (since the cross-sectional areas are congruent), and the height is 6 units. Therefore, \[ V_{\text{cylinder}} = A \times 6 \]

Now, we can express the volumes in terms of \( A \):

  • Volume of the triangular prism: \[ V_{\text{prism}} = 2A \]
  • Volume of the cylinder: \[ V_{\text{cylinder}} = 6A \]

To compare the volumes, we can set up the relationship: \[ V_{\text{prism}} = 2A \] \[ V_{\text{cylinder}} = 6A \]

Now, we compare \( V_{\text{prism}} \) and \( V_{\text{cylinder}} \): \[ V_{\text{cylinder}} = 3 \times V_{\text{prism}} \] This means that the volume of the cylinder is three times the volume of the prism.

This leads us to the conclusion:

The volume of the triangular prism is not equal to the volume of the cylinder.