Question

A coin 22 mm in diameter contains 66 mm³ of metal. How thick is the coin? [Take


`\pi`
=3.142]​

Answer 1

0.17 (2d.p)

Explanation:

volume of cylinder= πr^2Xh

22/2=11 which is radius

11^2=121

121X3.142=380.182

380.182Xh=66

h=66/380.182=0.1736010648

Answer 2

3000/17281 mm

Explanation:

We can model this as a cylinder with a volume of 66 mm³, a radius of 11 mm, and an unknown height
`h` mm.

Using the formula for the volume of a cylinder,

`V=\pi r^2 h \\ \\ 66=11^2 \pi h \\ \\ h=(66)/(121\pi) \\ \\ h=(6)/(11\pi) \\ \\ h \approx (6)/(11(3.142)) \\ \\ h \approx 3000/17281`