$A$ sphere of $30 \ cm$ radius is dropped into a cylindrical vessel of $80 \ cm$ diameter,which is partly filled with water. If its level rises by $x \ cm$,find $x$ (in $cm$). (in $.5$)

The radius of a coin is $1\, cm$. If four of these coins are placed on a table so that the rim of each touches that of the other two,find the area of the unoccupied space between them. (in $cm^2$)

If the altitude of an equilateral triangle is $12 \sqrt{3} \text{ cm}$,then its area would be

$A$ cow is tied by a rope at the corner of a rectangular field. If the length of the rope is $14\, m$,then the area of the field which the cow could graze is.......$m^2$

$A$ can go round a circular path $8$ times in $40$ minutes. If the diameter of the circle is increased to $10$ times the original diameter,then the time required by $A$ to go round the new path once,travelling at the same speed as before,is (in $min$)

The diagonals of a rhombus are $12 \ cm$ and $16 \ cm$. The length of one side is.......$cm$