Question

The cost of levelling the ground of a circular region at a rate of Rs.2 per
square metre is Rs.4928. Find the radius of the ground.​

Answer 1

SolutioN :-

We know that

→ Total Cost of levelling = Rate × Area of region

→ 4928 = 2 × Area of region

→ 4928 / 2 = Area of region

→ Area of region= 2464sq .m

Thus ,

Area of circular region is 2464sq .m

We know that ,

★ Area of circle = πr²

⇒ 2464 = 22 / 7 × r^2

⇒ 2464 × 7 = 22 × r^2

⇒ 17248 = 22r^2

⇒ 17248 / 22 = r^2

⇒ 784 = r^2

⇒ r = √784

⇒ r = 28m

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Thus , The radius of the ground is 28m.