Q7 of 52 Page 145

A cylinder and a cone have equal bases. The height of the cylinder is 3 cm and the area of its base is 100 cm2.The cone is placed upon the cylinder. Volume of the solid figure so formed is 500 cm3. Find the total height of the figure.

Let the radius of base be r.

Let the height of cone = H


Height of cylinder, h = 3cm


Area of base, A = 100 sq. cm


As we know the area of circle is πr2


⇒ πr2 = 100 ….. (1)


Volume of complete solid figure,V = Volume of cone + volume of cylinder




It is given that volume of solid figure, V = 500 cubic cm


On substituting the value of V and πr2 from eq (1), we get,



⇒ H = 6 cm


Total height of figure = h + H = 3 + 6 = 9 cm


∴ total height is 9 cm


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