Find the area of a sector of a circle of radius 6 cm , if the angle of the sector is 60 o .

Given radius 6 cm and angle at the centre 60 ° of the sector of a circle. We know that the area of sector = θ 360 ° × π r 2 = 60 ° 360 ° × 22 7 × 6 2 = 18 . 857 cm 2 ≃ 18 . 9 cm 2 Hence, the area of a sector of a given circle is 18 . 9 cm 2 .

Find the cost of ploughing the circular field having diameter 10 meter and rate of ploughing is ₨ . 1 . 50 per square meter.

Given, diameter of the circular field is 10 meter. So, d = 10 meter We know that radius of the circle is half of the diameter. So, r = d 2 = 10 2 = 5 meter We know that perimeter of the circle is 2 πr . So, area of the circular filed = 3 . 14 × 2 × 5 = 31 . 4 meter Given the rate of ploughing is ₨ . 1 . 50 per meter. Total rate of ploughing the circular field is ₨ . 1 . 50 × 31 . 4 = ₨ . 47 . 1 Hence, the total cost of ploughing the circular field is ₨ . 47 . 1 .