Mariah is replacing the water heater in her home and is considering three different models. One of the things she is comparing is the volume of the cylindrical storage tank in each water heater. The dimensions of the storage tanks, in inches, are as follows.

• Water Heater X: r = 8.5 and h = 48
• Water Heater Y: r = 9.5 and h = 44
• Water Heater Z: r = 10.5 and h = 32

Which statement is true?
A.
Water heater X has the storage tank with the greatest volume.
B.
The storage tanks in all three water heaters have the same volume.
C.
Water heater Z has the storage tank with the greatest volume.
D.
Water heater Y has the storage tank with the greatest volume.

1 answer

To determine which water heater has the greatest volume, we can calculate the volume of each cylindrical storage tank using the formula for the volume of a cylinder:

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

where \( V \) is the volume, \( r \) is the radius, and \( h \) is the height.

Let's calculate the volume for each water heater:

  1. Water Heater X:

    • \( r = 8.5 \) inches
    • \( h = 48 \) inches

    \[ V_X = \pi (8.5)^2 (48) = \pi (72.25) (48) \approx 10916.5 \text{ cubic inches} \]

  2. Water Heater Y:

    • \( r = 9.5 \) inches
    • \( h = 44 \) inches

    \[ V_Y = \pi (9.5)^2 (44) = \pi (90.25) (44) \approx 12566.5 \text{ cubic inches} \]

  3. Water Heater Z:

    • \( r = 10.5 \) inches
    • \( h = 32 \) inches

    \[ V_Z = \pi (10.5)^2 (32) = \pi (110.25) (32) \approx 3492 \text{ cubic inches} \]

Now, let's summarize the approximate volumes:

  • \( V_X \approx 10916.5 \)
  • \( V_Y \approx 12566.5 \)
  • \( V_Z \approx 3492.0 \)

From our calculations, we see that:

  • Water Heater X has a volume of approximately 10916.5 cubic inches.
  • Water Heater Y has a volume of approximately 12566.5 cubic inches.
  • Water Heater Z has a volume of approximately 3492.0 cubic inches.

Thus, the statement D: "Water heater Y has the storage tank with the greatest volume" is true.