MediumMathematicsHigh School (9–10)Mensuration › Areas and PerimetersNumericalreal-lifeBoard Exam SAT

A circular pond has a radius of 14 m. A path 3.5 m wide is built all round the outside of the pond…

Try it on paper first. A hint, the key idea and the worked solution are here when you need them.

A circular pond has a radius of $14\ \text{m}$ . A path $3.5\ \text{m}$ wide is built all round the outside of the pond. Paving costs $80$ rupees for each square metre. Find the area of the path and the cost of paving it. Take $\pi = \dfrac{22}{7}$ .

Need a reminder? The key ideaShow

A ring has area $\pi(R^2 - r^2)$ . If a chord of the big circle touches the small circle, the area of the ring is $\pi \times (\text{half the chord})^2$ . A path outside a circle adds its width to the radius.

The worked solution

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