ACT · Plane Geometry · Three-dimensional figures
Question act-q-00496
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The question
A cylinder has radius 8 and height 12. What is its volume, in terms of π?
- 96π
- 76π
- 768π
- 192π
Show answer & worked solution
Answer: 768π
Worked solution. Volume of a cylinder is πr²h. Here r = 8 and h = 12, so V = π × 8² × 12 = 768π.
Why each wrong choice is wrong. The 2πr × h distractor confuses lateral surface area with volume. Memorize both formulas separately.
Test-day tactic. Volume formula for any prism or cylinder: base area × height. For a cylinder, base area is πr².
About this question type
Items test volume and surface area for the standard solids: rectangular prisms, cylinders, cones, spheres, and pyramids.
You will see a question shaped like this one on roughly every other official ACT form, typically at the back end of the section, where the score gradient is steepest. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.