Lighthouse Initiative for Texas Classrooms

Teacher Guide and Answer Key, Middle School Activity 3

Based on AP* Calculus AB Problem 5, 1995

This is a good Pre-AP* worksheet because it expects students to combine many different concepts and skills responding to a single scenario, much like an AP* test question does. Students have to be able to interpret the questions and select appropriate strategies. There are opportunities to discuss things pertaining to units and the different forms that the answers may take.

illustration of an inverted cone with 6ft radius, h height for liquid, and 15ft overall height for cone

Oil is being stored in a conical storage tank having a radius of 6 feet and a height of 15 feet.



1. What is the capacity of the storage tank?
180 pie cubic feet

2. What is the ratio of the tank radius to its depth?
r over h equals 2 over 5

3. If the height of the oil in the tank is 10 ft, what is the radius of the oil in the tank?
r equals 4 feet

4. What is the volume of oil in the tank?
160 pie over 3 cubic feet

5. What is the ratio of the volume of the oil to the capacity of the tank?
8 over 27

6. What is the ratio of the radius of the oil to the radius of the tank?
2 over 3

7. What is the relationship between your answers to #5 and #6?
number 5 is the cube of number 6

8. What is the area of the surface of the oil in the tank?
16 pie square feet

9. If the oil currently in the tank is pumped out at a rate of 2 cubic feet/minute, how long will it take to empty the tank?
80 pie over 3 minutes or 83.776 minutes or 1 hour 23 minutes and 47 seconds

10. If the oil currently in the tank is pumped into another tank that is a right cylinder with a radius of 8 feet and a depth of 12 feet, what will be the depth of the oil in this new tank?
5 over 6 feet or .833 feet or 10 inches

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