Question : The slant height of a cone is 20 cm. If the area of its base is 616 cm², then what is the curved surface area of this cone? (use $\pi=\frac{22}{7}$)

Option 1: 960 cm²

Option 2: 400 cm²

Option 3: 1760 cm²

Option 4: 880 cm²

Question : The lateral surface area of a frustum of a right circular cone, if the area of its base is 16$\pi$ cm², the diameter of the circular upper surface is 4 cm and the slant height is 6 cm, will be:

Option 1: $30\pi$ cm²

Option 2: $48\pi$ cm²

Option 3: $36\pi$ cm²

Option 4: $60\pi$ cm²

Question : If the slant height of a cone is 60 cm and the radius of its base is 21 cm, then find its curved surface area is? (use $\pi=\frac{22}{7}$)

Option 1: 3880 cm²

Option 2: 3820 cm²

Option 3: 3960 cm²

Option 4: 4020 cm²

Question : What is the whole surface area of a cone with a base radius of 6 cm and height of 8 cm?

Option 1: 354.50 cm²

Option 2: 350.51 cm²

Option 3: 301.71 cm²

Option 4: 364.61 cm²

Question : The volume of a cone whose radius of a base and height are $r$ cm and $h$ cm respectively, is 400 cm³. What will be the volume of a cone whose radius of base and height are $2r$ cm and $h$ cm respectively?

Option 1: 100 cm³

Option 2: 1600 cm³

Option 3: 1200 cm³

Option 4: 800 cm³