volume_mute
Circumference Using the Diameter
publish date:Β 2026/05/17 03:18:34.649284 UTC
volume_mute
A tire has a diameter of 15 inches. Use the formula \(C = \pi D\) to find its circumference. Give the exact answer and an approximation using \(\pi \approx 3.14\).
Correct Answer
Exact: \(15\pi\) in; Approx: \(\approx 47.1\) in
Explanation
Using \(C = \pi D\) with \(D = 15\):
\[C = \pi(15) = 15\pi \text{ in (exact)}\]
\[C \approx 15 \times 3.14 = 47.1 \text{ in (approx)}\]
Note: option 2 would be correct if 15 were the radius, giving \(C = 2\pi(15) = 30\pi\). Since 15 is the diameter, we use \(C = \pi D\) directly.
Reference
Mathematics for college students