A) A rectangle measures 5 inches by 10 inches. It is dilated using a scale factor of 2.5. What is

the area in square inches of the dilated rectangle? (1 point)
312.5
250
50
100
278.3
A) Calculate and compare the surface area of sphere A, which has a radius of 4in and sphere B
which has a radius of 10 in. The formula for the surface area of a sphere is 4πr
2
(1 point)
Sphere A has a surface area of 4π in
2 and sphere B has a surface area of 10π in
2
, meaning sphere
B's surface area is 4 times as large as sphere A's.
Sphere A has a surface area of 64π in
2 and sphere B has a surface area of 400π in
2
, meaning
sphere B's surface area is 6.25 times as large as sphere A's.
Sphere A has a surface area of 8π in
2 and sphere B has a surface area of 20π in
2
, meaning sphere
B's surface area is 2.5 times as large as sphere A's.
Sphere A has a surface area of 16π in
2 and sphere B has a surface area of 40π in
2
, meaning
sphere B's surface area is 5 times as large as sphere A's.

1 answer

A) To find the area of the dilated rectangle, we first calculate the area of the original rectangle and then apply the scale factor.

The area of the original rectangle is: \[ \text{Area} = \text{Length} \times \text{Width} = 5 , \text{inches} \times 10 , \text{inches} = 50 , \text{square inches}. \]

When the rectangle is dilated by a scale factor of 2.5, the dimensions of the rectangle become: \[ \text{New Length} = 5 \times 2.5 = 12.5 , \text{inches}, \] \[ \text{New Width} = 10 \times 2.5 = 25 , \text{inches}. \]

Now, we calculate the area of the dilated rectangle: \[ \text{Area} = \text{New Length} \times \text{New Width} = 12.5 , \text{inches} \times 25 , \text{inches} = 312.5 , \text{square inches}. \]

So the area of the dilated rectangle is 312.5 square inches.


B) To compare the surface areas of sphere A and sphere B, we first use the formula for the surface area of a sphere: \[ \text{Surface Area} = 4 \pi r^2. \]

For Sphere A with a radius of 4 inches: \[ \text{Surface Area}_A = 4 \pi (4^2) = 4 \pi (16) = 64 \pi , \text{square inches}. \]

For Sphere B with a radius of 10 inches: \[ \text{Surface Area}_B = 4 \pi (10^2) = 4 \pi (100) = 400 \pi , \text{square inches}. \]

Now, we compare their surface areas: The ratio of Sphere B's surface area to Sphere A's surface area is: \[ \frac{\text{Surface Area}_B}{\text{Surface Area}_A} = \frac{400 \pi}{64 \pi} = \frac{400}{64} = 6.25. \]

This means that Sphere B's surface area is 6.25 times as large as Sphere A's.

Therefore, the correct comparison is: Sphere A has a surface area of 64π in² and sphere B has a surface area of 400π in², meaning sphere B's surface area is 6.25 times as large as sphere A's.