Question

How far does the tip of the minute hand of a clock move in 20 minutes if the hand is 10 inches long?

Answer 1

20.95 inches

Explanation:

The complete revolution of the minute hand forms a circle in 60 minutes.

circumference of a circle = 2
`\pi` radius

i.e C = 2
`\pi`r

But from the question, r = length of the minute hand = 10 inches

⇒ C = 2
`\pi` x 10

= 20
`\pi`

C = 20
`\pi` inches

Also, 20 minutes =
`(20 minutes)/(60 minutes)` =
`(1)/(3)` of the circumference.

So that,

the distance of the tip of the minute hand =
`(1)/(3)` x C

=
`(1)/(3)` x 20
`\pi`

=
`(1)/(3)` x 20 x
`(22)/(7)`

= 20.9524

= 20.95 inches

Thus, the distance of the tip of the minute hand is 20.95 inches