A right circular cylinder has a height of 8 meters (m) and a base with a radius of 12 m....
GMAT Geometry & Trigonometry : (Geo_Trig) Questions
A right circular cylinder has a height of \(8\) meters (m) and a base with a radius of \(12\) m. What is the volume, in \(\mathrm{m}^3\), of the cylinder?
\(8\pi\)
\(20\pi\)
\(768\pi\)
\(1{,}152\pi\)
1. TRANSLATE the problem information
- Given information:
- Height of cylinder: 8 meters
- Radius of base: 12 meters
- Need to find: Volume in m³
2. INFER the approach
- This is a cylinder volume problem, so we need the formula \(\mathrm{V = \pi r^2h}\)
- We have both radius and height, so we can substitute directly
3. SIMPLIFY the calculation
- Substitute the values: \(\mathrm{V = \pi(12)^2(8)}\)
- Calculate the exponent: \(\mathrm{12^2 = 144}\)
- Multiply: \(\mathrm{V = \pi(144)(8) = 1,152\pi}\)
Answer: D. \(\mathrm{1,152\pi}\)
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak SIMPLIFY execution: Students make calculation errors when squaring the radius or performing the final multiplication.
For example, they might calculate \(\mathrm{12^2}\) as 24 instead of \(\mathrm{144}\), or make errors in multiplying \(\mathrm{144 \times 8}\). This leads to selecting an incorrect answer choice or getting confused about which option matches their result.
Second Most Common Error:
Poor TRANSLATE reasoning: Students accidentally switch the radius and height values in their calculation.
They might use \(\mathrm{V = \pi(8)^2(12)}\) instead of \(\mathrm{V = \pi(12)^2(8)}\), which gives \(\mathrm{V = \pi(64)(12) = 768\pi}\). This may lead them to select Choice C (\(\mathrm{768\pi}\)).
The Bottom Line:
This problem tests whether students can accurately recall and apply the cylinder volume formula while maintaining precision in their arithmetic calculations.
\(8\pi\)
\(20\pi\)
\(768\pi\)
\(1{,}152\pi\)