Jude says that the volume of a square pyramid with base edges of 9.7 in and a height of 9 in is equal to the volume of a cylinder with a radius of 5.47 in and a height of 3 in. Jude rounded his answers to the nearest whole number. Examine Jude's calculations. Is he correct? (4 points)

Volume of Square Pyramid Volume of Cylinder
V = one third B(h) V = πr2h
V = one third(94.09)(9) V = π(5.472)(3)
V = one third(846.81) V = π(29.9209)(3)
V = 282 in3 V = π(89.7627)

V ≈ 282 in3

Yes, his calculations are correct and the volumes for figures are equal.

No, he made a mistake in solving for the volume of the cylinder.

Yes, but he made a mistake in solving for the volume of the square pyramid.

No, he made a mistake in solving for the volume of both figures.

1 answer

To determine whether Jude's calculations are correct, we will calculate the volumes of both the square pyramid and the cylinder step by step.

Volume of the Square Pyramid:

The volume \( V \) of a square pyramid can be calculated using the formula:

\[ V = \frac{1}{3} B h \]

where \( B \) is the area of the base and \( h \) is the height. The base is a square with edges of 9.7 inches, so the area \( B \) can be calculated as:

\[ B = (9.7)^2 = 94.09 \text{ in}^2 \]

Now, using the height \( h = 9 \text{ in} \):

\[ V = \frac{1}{3} (94.09) (9) = \frac{1}{3} (846.81) \approx 282.27 \text{ in}^3 \]

Rounded to the nearest whole number, the volume of the square pyramid is 282 in³.


Volume of the Cylinder:

The volume \( V \) of a cylinder is given by the formula:

\[ V = \pi r^2 h \]

where \( r \) is the radius and \( h \) is the height. Given a radius of 5.47 inches and height of 3 inches, we can compute:

First, calculate \( r^2 \):

\[ r^2 = (5.47)^2 \approx 29.9209 \text{ in}^2 \]

Now, substituting this into the volume formula:

\[ V \approx \pi(29.9209)(3) \approx 3.14159 \times 89.7627 \approx 282.61 \text{ in}^3 \]

Rounded to the nearest whole number, the volume of the cylinder is 283 in³.


Comparison of Volumes:

  • Volume of the square pyramid: 282 in³
  • Volume of the cylinder: 283 in³

Conclusion:

Since the volumes of the square pyramid and the cylinder are not equal (282 in³ ≠ 283 in³), Jude made a mistake.

The correct answer is: No, he made a mistake in solving for the volume of the cylinder.