Surface Area of a Right Circular Cone

Q.

The radius and height of a cone are in the ratio 4: 3. The area of the base is 154 cm². The area of the curved surface of cone is ___

1. $192.5{\text{cm}}^2$
2. $212.5{\text{cm}}^2$
3. $100.5{\text{cm}}^2$
4. $102.5{\text{cm}}^2$

Q.

A metal sheet of breadth $10cm$ is used to make a cone of radius $14cm$ and slant height $20cm$. Then length of sheet if $25\%$ of sheet is wasted is .

1. $1.99m$
2. $1.77m$
3. $1.82m$
4. $1.54m$

Q. The diameters of two cones are equal. If their slant heights are in the ratio 4:9, then the ratio of their curved surface areas is ________.

1. 2:3
2. 3:2
3. 4:9
4. 9:4

Q. CSA of cone of radius r, height h and slant height l is $\mathrm{\pi rl}$.

1. True
2. False

Q.

The diameters of two cones are equal. If their slant heights are in the ratio 3:4, then find the ratio of their curved surface areas.

1. 3 : 5

2. 5 : 4

3. 2 : 3

4. 3 : 4

Q.

Find the curved surface area of a cone whose radius is 14cm and slant height is 10 cm

1. 110 sq. cm

2. 240 sq. cm

3. 220 sq. cm

4. 440 sq. cm

Q. If the area of a circle with radius 'r' is equal to CSA of a cone of radius 'R' and slant height 'L', then R = .

1. $\frac{r^2}{L}$
2. $\pi RL$
3. $rL$

Q. The slant height of a cone is increased by $10\%$. If the radius remains the same, the curved surface area is increased by _____.

1. $20\%$
2. $10\%$
3. $12.1\%$
4. $21\%$

Q. The diameters of two cones are equal. If their slant heights are in the ratio 5:4, then the ratio of their curved surface areas is ________.

1. 4:5
2. 25:16
3. 16:25
4. 5:4

Q.

Raghu wants to make a closed aluminium cone for his science project. The slant height and radius of the cone should be 10 cm and 7 cm respectively. The area of the aluminium sheet required to make the cone is_____.
$(Use\pi =\frac{22}{7})$

1. $267{cm}^2$

2. $400{cm}^2$

3. $258{cm}^2$

4. $374{cm}^2$

Q. What is the approximate total surface area of a right circular cone of height 14 cm and base radius 7 cm? $\left(inc{m}^2\right)$

1. 344
2. 430
3. 499
4. 550