Right Circular Cone and Its Surface Area

Q. From a solid right circular cylinder of height 2.4 cm and radius 0.7 cm, a right circular cone of same the height and same radius is cut out. Find the total surface area of the remaining solid.

Q. Which among the given options correctly represents the pair of figures we get when we cut open the right circular cone(closed at the bottom) of radius(r) and slant height(l)?

1. None of the above
2. 
3. 
4. 

Q. The radius of the base of a right circular cone is 21 cm and its height is 20 cm. Find its volume.

1. $3300c{m}^2$
2. $1914c{m}^2$
3. $1386c{m}^2$
4. $26720c{m}^2$

Q.

The lateral surface area of a right circular cone of height 28 cm and base radius 21 cm is:

1. 1055 $c{m}^2$

2. 1155 $c{m}^2$

3. 2110 $c{m}^2$

4. 2310 $c{m}^2$

Q.

There is a coin. Ram attaches a conical attachment to one flat end of coin. The conical attachment has same radius as coin. What is the surface area of the combined solid?

1. Coin base area + Coin C.S.A + Hemisphere C.S.A

2. Total surface area of cone

3. Coin base area + Coin C.S.A + cone C.S.A

4. Total surface area of coin + total surface area of cone

Q. If a hemisphere of radius 21 cm is melted and recast to form a cone of height 42 cm, then the radius of cone is ___.

1. $1:2$
2. $2\sqrt{3}:\sqrt{5}$
3. $2\sqrt{2}:3$
4. $\sqrt{2}:\sqrt{3}$

Q. The diameter of the base of a right circular cone is 42 cm and its height is 20 cm. Find the curved surface area of the cone.

1. $3300c{m}^2$
2. $1386c{m}^2$
3. $1914c{m}^2$
4. $26720c{m}^2$

Q. The height of a conical tent is $14m$ and its floor area is $346.5m^2$. The length of canvas, $1.1m$ wide, required for it is:

1. $490m$
2. $525m$
3. $665m$
4. $860m$

Q. The base of a cone need not to be circular in shape.

1. True
2. False

Q. Total surface area of a cone of radius 5 cm and slant height 10 cm is .
$(Take\pi =3.14)$

1. $235.5c{m}^2$
2. $335.5c{m}^2$
3. $245c{m}^2$
4. $437c{m}^2$