Mathematics
How many cubic meters of earth must be dug out to make a well 28 m deep and 2.8 m in diameter ? Also, find the cost of plastering its inner surface at ₹ 4.50 per sq meter.
Related Questions
The total surface area of an open pipe of length H cm, external radius R cm and internal radius r cm, is :
πR2 - πr2 + 2π(R - r)H
2πR2 - 2πr2 + 2πRH
2πRH - 2πrh + πR2 - πr2
2(πR2 - πr2) + 2πRH + 2πrH
The inner radius of a pipe is 2.1 cm. How much water can 12 m of this pipe hold ?
What length of solid cylinder 2 cm in diameter must be taken to recast into a hollow cylinder of external diameter 20 cm, 0.25 cm thick and 15 cm long?
A cylinder has a diameter of 20 cm. The area of curved surface is 100 cm2. Find :
(i) the height of the cylinder correct to one decimal place.
(ii) the volume of the cylinder correct to one decimal place.