Question
Find the radius $ r $ of a cylinder if height $h = 20\, \text{ft}$ and volume $V = 320\pi\, \text{ft}^3$.
Answer
$\dfrac{ 4 }{ 5 }\, \text{ft}$
Explanation
To find radius $ r $ use formula:
$$ V = h ^{ 2 } \cdot r \cdot \pi $$After substituting $V = 320\pi\, \text{ft}^3$ and $h = 20\, \text{ft}$ we have:
$$ 320\pi\, \text{ft}^3 = 400\, \text{ft}^2 \cdot r \cdot \pi $$$$ r = \dfrac{ 320\pi\, \text{ft}^3 }{ 400\, \text{ft}^2 \, \pi} $$$$ r = \frac{ 4 }{ 5 }\, \text{ft} $$This page was created using
Cylinder Calculator