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Mathematics>Standard Multiple Choice

Read the following SAT test question and then click on a button to select your answer.

A right circular cylinder has height 6 and volume 54π. What is the circumference of its base?

(A) 2π
(B) 3π
(C) 6π
(D) 9π
(E) 18π

答案和解析

答案：C

解析：

The volume of a cylinder with radius r and height h is equal to π (r^2) *h. Therefore, π (r^2) *(6) = 54 *π and r^2 = 9, so the radius of the cylinder is 3. The circumference of a circle with radius r is equal to 2 *π r; therefore, the circumference of the base is equal to 6 *π.