1. True
2. True
3. The surface area of a sphere is given by the formula A = 4Ï€r^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 = 4Ï€(9)^2
A = 4Ï€(81)
A = 324Ï€
Therefore, the correct surface area should be 324Ï€, which is approximately 1017.88.
4. The surface area of a sphere is given by the formula A = 4Ï€r^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 = 4Ï€(15)^2
A = 4Ï€(225)
A = 900Ï€
Therefore, the correct surface area should be 900Ï€, 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.