ACT · Plane Geometry · Three-dimensional figures
Question act-q-00493
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The question
A cylinder has radius 7 and height 6. What is its volume, in terms of π?
- 55π
- 42π
- 84π
- 294π
Show answer & worked solution
Answer: 294π
Worked solution. Volume of a cylinder is πr²h. Here r = 7 and h = 6, so V = π × 7² × 6 = 294π.
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 a moderate position in the section — solidly within the range that separates a 600-band student from a 700-band student. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.