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25/06/2021 1:42 pm
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Find the area of the shaded region in Figure, if radii of the two concentric circles with centre O are 7 cm and 14 cm respectively and AOC = 40°.
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25/06/2021 1:44 pm
Given, Angle made by sector = 40°
Radius the inner circle = r = 7 cm
Radius of the outer circle = R = 14 cm
Area of the sector = (θ/360°) × πr2
So, Area of OAC = (40°/360°) × πr2 cm2
= 68.44 cm2
Area of the sector OBD = (40°/360°) × πr2 cm2
= (1/9) × (22/7) × 72 = 17.11 cm2
Now, area of the shaded region ABDC = Area of OAC – Area of the OBD
= 68.44 cm2 – 17.11 cm2
= 51.33 cm2