Remember the following formulae:

Area of sector =  x r² x /360

Area of triangle = ½ a b  sinC

We use these formulae to find the area of a segment.

Example

If R = 20 cm and   = 60º,

the area of the sector =  x 20 x 20 x 60 ÷ 360 = 209.44

the area of the triangle = ½ x 20 x 20 x sin 60º = 173.21

So the area of the segment = 209.44 - 173.21 = 36.23 cm²

Give all answers to 2 decimal places in this worksheet.