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If the diameter and the height of a cylinder are 10 cm and 10.5 cm, respectively, then using π=722, find the volume of the cylinder.
825 cm3
985 cm3
785 cm3
888 cm3
825 cm3
Calculate radius r = d/2 = 5. Then volume = (22/7) * 5 * 5 * 10.5. Since 10.5/7 = 1.5, calculate 22 * 25 * 1.5 = 22 * 37.5 = 825.
Diameter of cylinder d = 10 cm, Height of cylinder h = 10.5 cm, Constant pi = 22/7
V=πr2h
Calculate radius r = d/2 = 5. Then volume = (22/7) * 5 * 5 * 10.5. Since 10.5/7 = 1.5, calculate 22 * 25 * 1.5 = 22 * 37.5 = 825.
Confusing diameter with radius; ensure you divide the diameter by 2 before squaring it.
Find the radius
The radius r is half of the diameter d.
r=2d=210=5 cm
Apply Volume formula
Substitute r=5 cm and h=10.5 cm into the cylinder volume formula.
V=πr2h=722×52×10.5
Calculate the result
Simplify the expression: V=722×25×10.5. Since 10.5/7=1.5, we get V=22×25×1.5=22×37.5=825.
V=825 cm3
A is correct because the volume of the cylinder is calculated as 825 cm³ using the formula V=πr2h.
This concept is fundamental to 3D geometry problems in competitive exams; always check if the question provides diameter or radius to avoid the common division error.