Question

in the given figure two concentric circle with Centre O have radii 21 cm and 42 CM if angle AOB is equal to 60 degree find the area of the shaded region is (use
$\pi$
is equal to 22/7)

Answer 1

Hi There!

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OD = Radius of Smaller Circle = 21 cm

OB = Radius of Bigger Circle = 42 cm

Area of Major Sector OAB = (360-θ)/360° × πr²

Area of Major Sector OAB = (360-60)/360° × 22/7 × 42 × 42

Area of Major Sector OAB = 300/360  × 22  × 6  ×42

Area of Major Sector OAB = 5/6  × 22  × 42  × 6

Area of Major Sector OAB = 5 × 22 × 42

Area of Major Sector OAB =  4620 cm²

Ar(Smaller Circle) = πr²

Ar(Smaller Circle) = 22/7 × 21 × 21

Ar(Smaller Circle) = 22 × 3 × 21

Ar(Smaller Circle) = 1386 cm²

Ar(Shaded Region) = Ar(Major Sector) - Ar(Smaller Circle)

Ar(Shaded Region) =  4620 cm² - 1386 cm²

Ar(Shaded Region) = 3234 cm²

Therefore, Area of Shaded region = 3234 cm²

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Answer 2

Answer:

3465 m^2

Step-by-step explanation:

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