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

The prism has a larger volume by 13
times.
The prism has a larger volume by Start Fraction 1 over 3 End Fraction times.

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

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

To determine which shape has a larger volume and by how much, we need to calculate the volumes of both the triangular pyramid and the triangular prism.

Volume of the Triangular Pyramid

The formula for the volume of a triangular pyramid (also called a tetrahedron) is:

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

Base Area Calculation

To find the area of the triangular base, we can use the formula for the area of a triangle:

\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \]

To find the height of the triangle, we can use Heron's formula since we have the lengths of all three sides. However, we only know two (3 inches and 5 inches) and need the third side to calculate the area. We can deduce that, if this is a right triangle, the third side could be calculated using the Pythagorean theorem. For simplicity, let's consider the area calculation as sufficient using:

\[ \text{Area of triangle with sides a = 3, b = 5 and angle between them = 90 degrees} \]

Assuming it’s a right triangle:

Let \(b\) = 3 inches, \(h\) = 5 inches

\[ \text{Area} = \frac{1}{2} \times 3 \times 5 = 7.5 \text{ square inches} \]

Volume of Pyramid:

Given the height (h) of the pyramid is 8.41 inches:

\[ V_{pyramid} = \frac{1}{3} \times 7.5 \times 8.41 \] \[ V_{pyramid} = \frac{1}{3} \times 63.075 = 21.025 \text{ cubic inches} \]

Volume of the Triangular Prism

The volume of a triangular prism is given by the formula:

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

Using the same base area (7.5 square inches):

The height of the prism is given as 8.41 inches.

\[ V_{prism} = 7.5 \times 8.41 = 63.075 \text{ cubic inches} \]

Comparing Volumes

  • Volume of the pyramid = 21.025 cubic inches
  • Volume of the prism = 63.075 cubic inches

Now, we find the difference:

\[ \text{Difference} = V_{prism} - V_{pyramid} = 63.075 - 21.025 = 42.05 \text{ cubic inches} \]

Conclusion

The triangular prism has a larger volume than the triangular pyramid. To determine how many times larger:

\[ \text{Ratio} = \frac{V_{prism}}{V_{pyramid}} = \frac{63.075}{21.025} \approx 3 \]

Hence, the final conclusion is:

The prism has a larger volume by three times.