Q13 of 79 Page 238

A right angled ΔABC with sides 5 cm, 12 cm and 13 cm is revolved about the fixed side of 12 cm. Find the volume of the solid generated.

GIVEN : Δ ABC with right angle at B


AC will be the hypotenuse = 13cm


AB = 12cm


BC = 5cm


we take π =


TO FIND : volume of the solid generated = ?


PROCEDURE :


The solid formed on rotating the ΔABC about AB is a cone with radius “r” = 5cm


And height “h” = 12cm


∴ volume of the cone “V” = × π r2h


= × × (5)2 × 12


= × 25 × 4


= cm3


∴ volume of the solid generated ie. Cone is cm3


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