The circumference formula is
C = [tex]2 \pi [/tex]r
We know the circumference, so lets find the radius and we will get the diameter.
31.4 = 2[tex] \pi r[/tex]
divide by 2[tex] \pi [/tex] to isolate r
[tex] \frac{31.4}{2 \pi } [/tex] = [tex] \frac{2 \pi r}{2 \pi } [/tex]
2[tex] \pi [/tex] and 2[tex] \pi [/tex] cancels out.
0.4997 = r
0.5 in ≈ r (approximately)
Diameter is 2 × radius
2 × 0.5
1 in
