Find 1/12th of the volume of a hemisphere whose radius radius is 4.2…

Volume of a hemisphere = $\frac{2}{3} \pi r^3$

radius = 4.2

Volume = $\frac{2}{3} \pi 4.2^3$

           = $\frac{2}{3} \frac{22}{7} 4.2 \times 4.2 \times 4.2$    

           = 2 x 22 x 0.2 x 4.2 x 4.2

           = 155.232 m³

1/12th of the volume = $\frac{1}{12}$ x 155.232

                                = 7.3 m³