A cylinder has a surface area of 312π ft.2 . If its height is 20 ft., what is the measure of its radius?(1 point) Responses 6 ft. 6 ft. 5.5 ft. 5.5 ft. 5 ft. 5 ft. 6.5 ft. 6.5 ft.

Answer 1

To find the radius of the cylinder, we first need to calculate the lateral surface area of the cylinder using the formula:

Lateral Surface Area = 2πrh

Where r is the radius and h is the height of the cylinder.

Given that the lateral surface area is 312π ft^2 and the height is 20 ft:

312π = 2πrh
312 = 2rh
156 = rh

Since the height is 20 ft, we can substitute that into the equation:

156 = r(20)
r = 156/20
r = 7.8 ft

Therefore, the radius of the cylinder is 7.8 ft. None of the given options match this answer, so there seems to be an error in the options provided.