7.2 Volume: The Disk Method 405
____ 15. Find the volume of the solid generated by revolving the region bounded by the
graphs of the equations , and about the -axis. Round your
answer to four decimal places.
a. 5.3098
b. 12.2824
c. 20.6444
d. 15.9387
e. 37.9232
____ 16. A tank on the wing of a jet aircraft is formed by revolving the region bounded by the
graph of and the x-axis about the x-axis, where x and y are measured in
meters. Find the volume of the tank. Round your answer to two decimal places.
a. 0.45 m3
b. 0.33 m3
c. 0.03 m3
d. 1.79 m3
e. 0.12 m3
____ 17. A tank on a water tower is a sphere of radius 65 feet. Determine the depth of the
water when the tank is filled to one-fourth of its total capacity. (Note: Use the zero or root feature of a
graphing utility after evaluating the definite integral.) Round your answer to two decimal places.
a. 20.66 feet
b. 54.63 feet
c. 34.67 feet
d. 42.43 feet
e. 10.36 feet