Answer:
A = 81π cm²
Explanation:
The area (A) of the cross section is calculated as
A = πr² ( r is the radius )
Find r by using the given circumference.
Given the circumference is 18π and circumference (C) is
C = 2πr = 18π ( divide both sides by 2π )
r = 9, thus
A = π × 9² = 81π cm²