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 $\pi=\frac{22}{7}$)

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:

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 $\pi=\frac{22}{7}$)

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

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?