$A$ cone and a cylinder have equal radii and equal heights. Then,the ratio of their volumes is $\ldots \ldots \ldots . .$

$A$ solid metallic hemisphere of radius $8 \, cm$ is melted and recast into a right circular cone of base radius $6 \, cm$. Determine the height of the cone (in $cm$).

The $TSA$ of a hemisphere with radius $10 \, cm$ is $\ldots \ldots \ldots \, cm^{2}$. (in $\pi$)

The ratio of the radii of two spheres is $3:4$. Then,the ratio of their volumes is $\ldots \ldots \ldots$

$A$ metallic sphere of radius $6 \, cm$ is melted and recast into a wire with diameter $1 \, cm$. Find the length of the wire in metres.

$A$ cylinder with radius $21 \, cm$ and height $18 \, cm$ is closed at both the ends by hemispheres. Find the surface area of this article. $(\pi = \frac{22}{7})$ (in $cm^2$)