Question

Perimeter of a sector of a circle whose central angle is 90° and radius 7 cm is ______.

Options

• 35 cm

• 25 cm

• 77 cm

• 7 cm

Answer 1

The perimeter of a sector of a circle whose central angle is 90° and radius 7 cm is 25 cm.

Explanation:

Perimeter of sector `= 2r + (2 pir theta)/360`

so for,

• r = 7 cm
• θ = 90^∘

`2 xx 7 + 2 xx 22/7 xx 7 xx 90/360`

= `14 + (2 xx 22 xx 7 xx 90)/(7 xx 360)`

= 14 + 11 = 25 cm