Surface Area of Spheres Quick Check
1. A sphere has a center
2. The diameter of a sphere passes through the center of the circle
3. 265.77
4. 900
5. 4.5 in. x 4.5in. x 4.5in.
1. True
2. True
3. The surface area of a sphere is given by the formula A = 4πr^2. If we substitute in the given value of 9 for the radius (since the diameter is 18), we can calculate the surface area as follows:
A = 4π(9)^2
A = 4π(81)
A = 324π
Therefore, the correct surface area should be 324π, which is approximately 1017.88.
4. The surface area of a sphere is given by the formula A = 4πr^2. If we substitute in the given value of 15 for the radius (since the diameter is 30), we can calculate the surface area as follows:
A = 4π(15)^2
A = 4π(225)
A = 900π
Therefore, the correct surface area should be 900π, which is approximately 2827.43.
5. To calculate the surface area of a cube, we use the formula A = 6s^2, where s is the length of one side. If we substitute in the given value of 4.5 for the side length, we can calculate the surface area as follows:
A = 6(4.5)^2
A = 6(20.25)
A = 121.5
Therefore, the correct surface area should be 121.5 square inches.