Question : Which of the following statements is not correct?

Option 1: For a given radius and height, a right circular cone has a lesser volume than a right circular cylinder.

Option 2: If the side of a cube is increased by 10%, the volume will increase by 33.1%.

Option 3: If the radius of a sphere is increased by 20%, the surface area will increase by 40%.

Option 4: Cutting a sphere into 2 parts does not change the total volume.

Question : What is the radius of a normal cylinder whose height is 21 cm and curved surface area is 1386 cm²?

Option 1: 10.5 cm

Option 2: 3.5 cm

Option 3: 7 cm

Option 4: 10 cm

Question : What is the curved surface area (in cm²) of a cylinder having a radius of base as 14 cm and height as 10 cm?

Option 1: 440

Option 2: 880

Option 3: 220

Option 4: 1320

Question : If the radius of a circle is increased by 10%, what will be the percentage increase in the area of the circle?

Option 1: 19

Option 2: 20

Option 3: 21

Option 4: 23

Question : The radius of the ends of a frustum of a solid right-circular cone 45 cm high is 28 cm and 7 cm. If this frustum is melted and reconstructed into a solid right circular cylinder whose radius of base and height are in the ratio 3: 5, find the curved surface area (in ${cm}^2$ ) of this cylinder. [Use $\pi=\frac{22}{7}$.]

Option 1: 4580

Option 2: 4610

Option 3: 4640

Option 4: 4620