Question

in the given go figure, two concentric circle with center o have radii 21 cm and 42 cm. If angle AOB = 60 then find the area of shaded region

Answer 1

 π R² - r² = (22/7) (42² - 21²) = 4158 cm²

Angle subtended by the arc in the inner circle = 60

Area of the sector in inner circle = (60° / 360°) x π r² = (60° / 360°) x (22/7) x (21)² = 231 cm²

 Angle subtended by the arc in  outer circle = 60°

Area of the sector in the inner circle = (60° / 360°) x π R² = (60° / 360°) x (22/7) x (42)² = 924 cm²

Area of portion of the sector in between circles = 924 - 231 = 693 cm²

Area of the shaded portion = Area between the circles - Area of the portion of the sector in between circles
                                       = 4158 - 693
                                       = 3465cm²

Answer 2

Step-by-step explanation:

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