Question

Find the length of arc AB for each circle.

Answer 1

see explanation

Explanation:

The length of the arc is calculated as

AB = circumference of circle × fraction of circle

(11)

AB = 2πr ×
`(90)/(360)`

= 2π × 7 ×
`(9)/(36)`

= 14π ×
`(1)/(4)`

=
`(7)/(2)` π in

(12)

AB = 2πr ×
`(135)/(360)` ( r = 20 ÷ 2 = 10 )

= 2π × 10 ×
`(3)/(8)`

= 20π ×
`(3)/(8)`

=
`(60)/(8)` π

=
`(15)/(2)` π cm