The radius of the cylinder is made twice as large. How should the height be changed so that the volume remains the same?

The perimeter of the base of a right circular cone is $132 \, cm$. If the height of the cone is $72 \, cm$,then what is the total surface area (in $cm^2$) of the cone?

The circumference of the base of a $9\, m$ high conical tent is $44\, m$. The volume of the air contained in it is.........$m^3$

$A$ hemispherical bowl is filled to the brim with a beverage. The contents of the bowl are transferred into a cylindrical vessel whose radius is $50 \%$ more than its height. If the diameter is same for both the bowl and the cylinder,the volume of the beverage in the cylindrical vessel is.........$\%$

The radius of the base of a conical tent is $5 \, m$. If the tent is $12 \, m$ high,then the area of the canvas required to make the tent is (in $\pi \, m^2$)

$A$ solid cone of height $36 \, cm$ and radius of base $9 \, cm$ is melted to form a solid cylinder of radius $9 \, cm$ and height $9 \, cm$. What percent of material is wasted in this process (in $\%$)?