Question

The circumference of a circular clock is 31.4 inches.What is the diameter of the clock

Answer 1

The circumference formula is
C =
`2 \pi`r

We know the circumference, so lets find the radius and we will get the diameter.

31.4 = 2
`\pi r`
divide by 2
`\pi` to isolate r


`(31.4)/(2 \pi )` =
`(2 \pi r)/(2 \pi )`
2
`\pi` and 2
`\pi` cancels out.

0.4997 = r
0.5 in ≈ r (approximately)

Diameter is 2 × radius
2 × 0.5
1 in

Answer 2

Circumference of a circle=πd
d=diameter
Circumference=31.4 in
π=3.141592654...

31.4 in=πd
d=3.14 in / π=0.999493...in≈1 in

Answer: diameter=1 in