Geometry Practice Test 6

Question : 3 of 39

Marks: +1, -0

The area of a sector of a circle is 77 sq. cm and the angle of the sector is 45°. Find the radius of the circle.

Solution:

Area of a sector of a circle = 77

cm^2

Angle of the sector = 45°
Area of a sector of circle =

{\angle}/{360°} × πr^2

77 =

{45°}/{360°} × {22}/7 × r^2

77 =

1/8 × {22}/7 × r^2

r^2

{8×7×77}/{22}

r^2

{4312}/{22}

r^2

= 196
r = 14 cm

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