Question

The area of a circle is 81π sq.cm. Find the length of the arc subtending an angle of 300° at the centre and also the area of corresponding sector.

Answer 1

Area of circle = πr² 

But area is given to be 81 n sq.cm 

∴ πr = 81π 

∴ r² = 81 

∴ r = 9 cm

θ = 300°=(300 x π/180)^c = (5π/3)^c

Since S = rθ 

S = 9 x = 5π/3 = 15π cm 

Area of sector = 1/2 x r x S 

= 1/2x 9 x 15π = 135π/2 sq.cm