Question

The radius of a circle is 21cm. An arc of the circle subtends an angle of `60@` at centre. Find the length of the arc?

Answer 1

21.98

Explanation:

A quick formula for this,
Arc length = `(theta/360)*2piR`

Where `theta` is the angle it subtends and `R` is radius

So, arc length = `(60/360)*2piR`

=`21.98`

Note: If you don't want to memorize the formula then think hard about it, you can easily understand its origin and come up with it on your own next time!