Q13 of 24 Page 227

Let us fill in the blanks:

(i) AC is the hypotenuse of a right-angle triangle ABC, the radius of the right circular cone formed by revolving the triangle once around the side AB as the axis is___


(ii) If the volume of a right circular cone is V cubic unit and the base area is A sq. unit, then its height is____


(iii) The lengths of the base radii and the heights of a right circular cylinder and a right circular cone are equal. The ratio of their volume is_____.

(i) BC


AC is equivalent to the slant height.


AB is equivalent to height.


BC is equivalent to radius.


(ii) We know,


Volume of a right circular cone = base area × height


⇒ V = A × height


⇒height = V/A


(iii) In 1st case,


Base radius = r


Height = h


∴ Volume, x = πr2h/3


In 2nd case,


Base radius = r


Height = h


∴ volume, y = πr2h/3


∴ x∶ y = (πr2h/3) ∶ (πr2h/3) = 1 ∶ 1


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Let us write whether the following statements are true or false:

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