When fully inflated, a blue exercise ball has a diameter of 56 cm. A similar red exercise ball, when fully inflated, has a diameter of 76 cm. Which statement is true?(1 point)

Responses

The volume of the red ball is about 1.5 times larger than the volume of the blue ball.
The volume of the red ball is about 1.5 times larger than the volume of the blue ball.

The volume of the blue ball is about 2.5 times larger than the volume of the red ball.
The volume of the blue ball is about 2.5 times larger than the volume of the red ball.

The volume of the blue ball is about 1.5 times larger than the volume of the red ball.
The volume of the blue ball is about 1.5 times larger than the volume of the red ball.

The volume of the red ball is about 2.5 times larger than the volume of the blue ball.

1 answer

To determine the relationship between the volumes of the blue and red exercise balls, we can use the formula for the volume of a sphere:

\[ V = \frac{4}{3} \pi r^3 \]

where \(r\) is the radius of the sphere.

First, we need to find the radius of each ball. The radius is half of the diameter.

For the blue ball:

  • Diameter = 56 cm
  • Radius = \( \frac{56}{2} = 28 \) cm

For the red ball:

  • Diameter = 76 cm
  • Radius = \( \frac{76}{2} = 38 \) cm

Now we can calculate the volume of each ball.

Volume of the blue ball: \[ V_{blue} = \frac{4}{3} \pi (28)^3 \]

Calculating \(28^3\): \[ 28 \times 28 \times 28 = 21952 \]

So, \[ V_{blue} \approx \frac{4}{3} \pi (21952) \approx 92019.5 \pi \]

Volume of the red ball: \[ V_{red} = \frac{4}{3} \pi (38)^3 \]

Calculating \(38^3\): \[ 38 \times 38 \times 38 = 54872 \]

So, \[ V_{red} \approx \frac{4}{3} \pi (54872) \approx 230312.5 \pi \]

Now, we can find the ratio of the volumes: \[ \frac{V_{red}}{V_{blue}} = \frac{230312.5 \pi}{92019.5 \pi} = \frac{230312.5}{92019.5} \]

Calculating this gives approximately: \[ \frac{230312.5}{92019.5} \approx 2.5 \]

This indicates that the volume of the red ball is about 2.5 times larger than the volume of the blue ball.

Therefore, the correct statement is: The volume of the red ball is about 2.5 times larger than the volume of the blue ball.