Exercise 17.2

The height and the radius of the base of a right circular cone is half the corresponding height and radius of another bigger cone. Find : the ratio of their lateral surface areas.

Find what length of canvas $2 \mathrm{m}$ in width is required to make a conical tent $20 \mathrm{m}$ in diameter and $42 \mathrm{m}$ in slant height allowing $10\%$ for folds and the stitching. Also find the cost of the canvas at the rate of $₹ 80$ per metre.

The perimeter of the base of a cone is $44 \mathrm{cm}$ and the slant height is $25 \mathrm{cm}$. Find the volume and the curved surface of the cone.

The volume of a right circular cone is $9856{ \mathrm{cm}}^3$ and the area of its base is $616{ \mathrm{cm}}^2$. Find the slant height of the cone.

The volume of a right circular cone is $9856{ \mathrm{cm}}^3$ and the area of its base is $616{ \mathrm{cm}}^2$. Find total surface area of the cone.

A right triangle with sides $6 \mathrm{cm},8 \mathrm{cm}$ and $10 \mathrm{cm}$ is revolved about the side $8 \mathrm{cm}$. Find the volume and the curved surface of the cone so formed. (Take $\pi =3.14$)

A semicircular lamina of radius $35 \mathrm{cm}$ is folded so that the two bounding radii are joined together to form a cone. Find : the (lateral) surface area of the cone.