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An illustration shows a triangular pyramid and a triangular prism. The edges that are not visible are marked as dashed lines. The triangular pyramid has the triangular face as its base. The sides of of the triangular base measure 3 inches and 5 inches. The perpendicular height of the pyramid is 8.41 inches. The triangular prism has its triangular face as the base. The sides of the triangular base measure 3 inches and 5 inches. The length of the side is 8.41 inches.

Which shape has the larger volume? How much larger is it?

(1 point)
Responses

The pyramid has a larger volume by three times.
The pyramid has a larger volume by three times.

The prism has a larger volume by three times.
The prism has a larger volume by three times.

The prism has a larger volume by 1/3 times.
The prism has a larger volume by Start Fraction 1 over 3 End Fraction times.

The volumes are the same.
The volumes are the same.
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1 answer

To compare the volumes of the triangular pyramid and triangular prism, we can use the formulas for their volumes.

  1. Volume of the Pyramid: \[ V_{\text{pyramid}} = \frac{1}{3} \times \text{Base Area} \times \text{Height} \]

    The base is a triangle, and we can calculate its area using the formula: \[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \] Since we don't have the height of the triangle, we use Heron's formula instead.

    First, we need the semi-perimeter (s) of the triangle: \[ s = \frac{3 + 5 + 6}{2} = 7 \] The sides are 3, 5, and we can find the third side using the Pythagorean Theorem in a 3-4-5 right triangle: \[ c = \sqrt{5^2 - 4^2} = \sqrt{25 - 16} = 3 \]

    Now, we can calculate the area using Heron's formula: \[ \text{Area} = \sqrt{s(s-a)(s-b)(s-c)} = \sqrt{7(7-3)(7-5)(7-6)} = \sqrt{7 \times 4 \times 2 \times 1} = \sqrt{28} \approx 5.29 \] Thus, \[ V_{\text{pyramid}} = \frac{1}{3} \times 5.29 \times 8.41 \approx 14.85 , \text{inches}^3 \]

  2. Volume of the Prism: \[ V_{\text{prism}} = \text{Base Area} \times \text{Height} \] Using the base area calculated earlier, \[ V_{\text{prism}} = 5.29 \times 8.41 \approx 44.45 , \text{inches}^3 \]

  3. Comparing Volumes: To find out how much larger the volume of the prism is compared to the pyramid, \[ \text{Difference} = V_{\text{prism}} - V_{\text{pyramid}} \approx 44.45 - 14.85 \approx 29.60 , \text{inches}^3 \]

Thus, the prism has a larger volume than the pyramid, and it is approximately 3 times larger.

The correct response is:

  • The prism has a larger volume by three times.