
Thank you!
Thank you!
Taking π =3.14
(a) Area of circle = πr2 = 400π
Area of shaded part = 420
Area of the part opp the shaded part = 420 (vertically opposite)
So area of non-shaded part = 400π – 420 -420 = 400π – 840 = 1256 – 840 = 416
Hence area of OPQRS = 420 + 416 = 836cm2
(b) Circumference of circle = 2π r = 2 x 3.14 x 20 = 125.6
Arc of shaded part = 78-20-20 = 38 Opposite side arc = 38
Hence length of arc for unshaded part = 125.6 – 38 – 38 = 49.6
Therefore, perimeter of OPQRS = 78 + 49.6 = 127.6cm
Opposite side arc = 38
May I know what is opposite arc?
Please click the diagram for explanation.