Question
The radius of a wheel is 21 cm. What is the distance (in cm) travelled by the wheel in 20 revolutions?
The correct answer is
2640 cm
For rolling without slipping, distance equals revolutions × circumference. Using π = 22/7, \(D=20(2\pi r)=20(2)(22/7)(21)=2640\ \mathrm{cm}\).
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Important Questions from Plane Figures
- A rectangular grassy plot is 38 m long and 32 m wide. It has a gravel path of uniform width on the inside having an area of $600 \text{ m}^2$. The width of the path is:
- A river, 2 m deep and 45 m wide is flowing at the speed of 3 km per hour. The quantity of water that runs into the sea per minute is:
A regular hexagonal garden with each side measuring 14 metres is surrounded by a circular jogging track that has a radius of 21 metres from the centre of the hexagon. Find the sum of the perimeters of both shapes.
(Use $\pi = \frac{22}{7}$)- If a circle and a square have the same perimeter, then
What is the area of this parallelogram in sq.cm.? The measurements are in cms.
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