Question

Calculate the perimeter of the sector of a circle whose angle at the centre is 140 degrees

Answer 1

ANSWER

Given−

AOBisasectorofradius=randthecentralangle=θ.

Tofindout−

theperimeterofthesectorAOB=?

Solution−

ThearclengthAB=

360

o

θ

×2×π×r=

360

o

πθ

×2r.

Nowtheperimeterofthesector=OA+OB+arcAB

=r+r+

360

o

θ

×2πr=2r(

360

o

πθ

+1).

Ans−OptionB.