The formula for the surface area of a sphere is 4πr^2. Sphere A has a radius of 3 cm and sphere B has a radius of 6 cm. Calculate the surface area of each sphere and compare their surface areas.

Sphere A has a surface are of __π cm^2. Sphere B has a surface area of ___π cm^2. The surface area of sphere B is __ times larger than the surface area of sphere A.

1 answer

To find the surface area of each sphere, we can use the formula for the surface area of a sphere:

\[ \text{Surface Area} = 4\pi r^2 \]

Calculating the surface area for Sphere A:

  • Radius \( r_A = 3 \) cm \[ \text{Surface Area of Sphere A} = 4\pi (3)^2 = 4\pi (9) = 36\pi , \text{cm}^2 \]

Calculating the surface area for Sphere B:

  • Radius \( r_B = 6 \) cm \[ \text{Surface Area of Sphere B} = 4\pi (6)^2 = 4\pi (36) = 144\pi , \text{cm}^2 \]

Summary of results:

  • Sphere A has a surface area of \( 36\pi \) cm².
  • Sphere B has a surface area of \( 144\pi \) cm².

Comparing the surface areas: To find out how many times larger the surface area of Sphere B is compared to Sphere A, we can divide the surface area of Sphere B by the surface area of Sphere A:

\[ \text{Ratio} = \frac{\text{Surface Area of Sphere B}}{\text{Surface Area of Sphere A}} = \frac{144\pi}{36\pi} = \frac{144}{36} = 4 \]

Thus, Sphere B's surface area is 4 times larger than that of Sphere A.

Final answers:

  • Sphere A has a surface area of \( 36\pi \) cm².
  • Sphere B has a surface area of \( 144\pi \) cm².
  • The surface area of Sphere B is 4 times larger than the surface area of Sphere A.