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If the lateral surface area of a cylinder is 775.8 cm 2 and its height is 24 cm, then find its volume. (Use ╧А = 3.14 and round off to two decimal places.)
1962.74 cm┬│
1984.78 cm┬│
2016.67 cm┬│
1996.63 cm┬│
1996.63 cm┬│
Calculate the radius first using r=2╧АhLSAтАЛ. Given 2╧АhтЙИ2├Ч3.14├Ч24=150.72, dividing 775.8 by 150.72 gives rтЙИ5.147. Then estimate volume V=╧Аr2h=(2LSAтАЛ)├Чr.
Lateral surface area of cylinder LSA = 775.8 cm┬▓, height h = 24 cm, and ╧А = 3.14.
LSA=2╧Аrh and V=╧Аr2h
Calculate the radius first using r=2╧АhLSAтАЛ. Given 2╧АhтЙИ2├Ч3.14├Ч24=150.72, dividing 775.8 by 150.72 gives rтЙИ5.147. Then estimate volume V=╧Аr2h=(2LSAтАЛ)├Чr.
Students often use the diameter instead of the radius in the volume formula or use the total surface area formula instead of lateral surface area.
Calculate the radius of the cylinder
Using the formula for lateral surface area LSA=2╧Аrh, substitute the known values to find r.
r=2├Ч3.14├Ч24775.8тАЛ=150.72775.8тАЛтЙИ5.1473
Calculate the volume of the cylinder
Substitute the value of r into the volume formula V=╧Аr2h.
V=3.14├Ч(5.1473)2├Ч24
Perform final multiplication
Calculate the square of the radius and multiply by ╧А and h to get the final volume.
V=3.14├Ч26.4947├Ч24тЙИ1996.63
D is correct because the calculated volume of the cylinder using the derived radius is approximately 1996.63 cm┬│.
This concept is essential for mensuration problems in SSC and banking exams where cylindrical pipes or tank capacities are frequently asked.