Question

A team in science class placed a chalk mark on the side of a wheel and rolled the wheel in a straight line until the chalk mark returned to the

same position. The team then measured the distance the wheel had rolled and found it to be 25 cm. To the nearest tenth, what is the area of
the wheel?

49.7 cm?
198.9 cm?
99.5 cm
19.6 cm?

Answer 1

49.7
`cm^(2)`

Explanation:

Although it is hidden a bit, we are actually given the circumference of the circle, which is 25 cm.

We know that C = 2πr, so we can substitute variables to find the radius (r).

25 = 2πr

r = 25/(2π)

r = 3.9788... cm

The area of a circle is A = π
`r^(2)`, so:

A = π
`3.9788^(2)`

A = 49.7359...
`cm^(2)`

A ≈ 49.7
`cm^(2)`