The wheel of the motorcycle is of radius $35 \mathrm{cm}$. How many revolutions per minute must the wheel make, so as to keep a speed of $66 \mathrm{km}/\mathrm{h}$?

Find the area of the flower bed (with semi-circular ends) shown in figure 

In figure, $AB$ is a diameter of the circle, $AC=6 \mathrm{cm}$ and $BC=8 \mathrm{cm}.$ Find the area of the shaded region. (use $\mathrm{\pi }=3.14$)

Find the area of the shaded field shown in figure

Find the area of the shaded region in figure. 

Find the area of the minor segment of a circle of radius $14 \mathrm{cm}$, when the angle of the corresponding sector is $60°$

Find the area of the shaded region in figure, where arcs drawn with centres  $A, B, C \mathrm{and} D$ intersect in pairs at mid-point $P,Q,R \mathrm{and} S$ of the sides $AB, BC, CD \mathrm{and} DA,$respectively of a square $ABCD$(use $\mathrm{\pi }=3.14$)

In figure arcs are drawn by taking vertices $A, B$ and $C$ of an equilateral triangle of side $10 \mathrm{cm}$, To intersect the sides $BC, CA$ and $AB$ at their respective mid-points $D, E$and $F$. Find the area of the shaded region. (use $\mathrm{\pi }=3.14$)