The arc of a circle of radius 20cm subtend an angle of 120° at the centre.use the value 3.142 for pie to calculate the area of the sector correct to the nearest cm square
Area of the whole circle = π(20^2) = 400π
so the area of your sector = 120/360 or 1/3 of that
area of your sector = (1/3)(400π)
= .... cm^2
I will let you do the calculations, I would use the π key on my calculator.