The radius of a hemispherical dome of a temple is $21\, m$. Find the cost of painting its outer surface at the rate of ₹ $80/m^2$. (in ₹)

Six wooden cubes of length $3 \, cm$ are arranged in a row touching each other face to face. Find the total surface area of the solid formed in this manner. (in $cm^2$)

Write 'True' or 'False' and justify your answer:
$A$ solid cone of radius $r$ and height $h$ is placed over a solid cylinder having the same base radius and height as that of the cone. The total surface area of the combined solid is $\pi[\sqrt{r^{2}+h^{2}}+3r+2h]$.

The dome of a temple is in the shape of a cone with radius $3.5\, m$ and height $12\, m$. Find the cost of painting its outer surface at the rate of ₹ $30/m^2$.

$A$ container,opened from the top and made up of a metal sheet,is in the form of a frustum of a cone of height $16 \, cm$ with radii of its lower and upper ends as $8 \, cm$ and $20 \, cm$,respectively. Find the cost of the milk which can completely fill the container,at the rate of $Rs. \, 20$ per litre. Also,find the cost of the metal sheet used to make the container,if it costs $Rs. \, 8$ per $100 \, cm^2$. (Take $\pi = 3.14$)

An oil funnel made of a tin sheet consists of a $10 \, cm$ long cylindrical portion attached to a frustum of a cone. If the total height is $22 \, cm$,the diameter of the cylindrical portion is $8 \, cm$,and the diameter of the top of the funnel is $18 \, cm$,find the area of the tin sheet required to make the funnel.