Use the image to answer the question.

An illustration shows an equilateral triangle with each side measuring 6 centimeters. The perpendicular height is shown as a dashed line from the base to the apex and and is 4 centimeters. A right angle symbol is shown to the right of the perpendicular line.

Use the model for the base of a triangular prism and triangular pyramid. If the heights are both 9 cm, what is the volume of each shape?

(1 point)
Responses

prism: 216 cm3; pyramid: 72 cm3
prism: 216 cm cubed ; pyramid: 72 cm cubed

prism: 72 cm3; pyramid: 216 cm3
prism: 72 cm cubed ; pyramid: 216 cm cubed

prism: 108 cm3; pyramid: 36 cm3
prism: 108 cm cubed ; pyramid: 36 cm cubed

prism: 36 cm3; pyramid: 108 cm3
prism: 36 cm cubed ; pyramid: 108 cm cubed
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1 answer

To find the volumes of the triangular prism and pyramid that both use the same triangular base, follow these steps:

1. Calculate the area of the triangular base.

The base of the triangle is an equilateral triangle with a side length of 6 cm. The formula for the area \( A \) of an equilateral triangle is:

\[ A = \frac{\sqrt{3}}{4} s^2 \]

Where \( s \) is the side length.

Plugging in the given side length:

\[ A = \frac{\sqrt{3}}{4} (6)^2 = \frac{\sqrt{3}}{4} \cdot 36 = 9\sqrt{3} \text{ cm}^2 \]

2. Calculate the volume of the triangular prism.

The formula for the volume \( V \) of a prism is:

\[ V = \text{Base Area} \times \text{Height} \]

The height of the prism is given as 9 cm. Therefore:

\[ V_{\text{prism}} = 9\sqrt{3} \times 9 = 81\sqrt{3} \text{ cm}^3 \]

Calculating \( 81\sqrt{3} \):

Since \( \sqrt{3} \) is approximately 1.732:

\[ V_{\text{prism}} \approx 81 \times 1.732 \approx 140.232 \text{ cm}^3 \]

3. Calculate the volume of the triangular pyramid.

The formula for the volume \( V \) of a pyramid is:

\[ V = \frac{1}{3} \times \text{Base Area} \times \text{Height} \]

Using the same base area \( 9\sqrt{3} \) cm² and a height of 9 cm:

\[ V_{\text{pyramid}} = \frac{1}{3} \times 9\sqrt{3} \times 9 = \frac{81\sqrt{3}}{3} = 27\sqrt{3} \text{ cm}^3 \]

Calculating \( 27\sqrt{3} \):

\[ V_{\text{pyramid}} \approx 27 \times 1.732 \approx 46.704 \text{ cm}^3 \]

4. Rounding to the nearest whole numbers:

Finally, rounding \( 140.232 \) and \( 46.704 \) gives us:

  • Volume of the prism: approximately 140 cm³
  • Volume of the pyramid: approximately 47 cm³

5. Select the closest option:

Comparing the calculated volumes with the options given:

  • Prism: 216 cm³; Pyramid: 72 cm³
  • Prism: 72 cm³; Pyramid: 216 cm³
  • Prism: 108 cm³; Pyramid: 36 cm³
  • Prism: 36 cm³; Pyramid: 108 cm³

None of the options exactly match, but it appears the information given might not be aligned with my calculations. If we strictly regard only the calculation process without numerical errors:

  1. Prism: 216 cm³ indicates a wrong base area interpretation with revised height considerations.
  2. Pyramid: 72 cm³ might be re-evaluated in respect to the pyramid's output derived geometrically.

Finalize with detailed review or possibly reconciling the specifications asked within problem scope.