Question
The boundary length (perimeter) of a semicircle is 72 m.
Find the area of a full circle whose radius is thrice the radius of that semicircle.Solution
ATQ,
Perimeter of the semi-circle = (π × radius) + 2 × radius = {(22/7) + 2} × radius = {(22 + 14)/7} × radius So, {(22 + 14)/7} × radius = 72 metres So, radius = 72 × (7/36) = 14 metres So, area of the circle with thrice the radius = π × 42 × 42 = (22/7) × 42 × 42 = 5544 m²
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