A hemispherical piece of metal of radius 42 cm is melted and part of t

1.	A hemispherical piece of metal of radius 42 cm is melted and part of this melted metal is utilised to make 4 cone of radius 20cm and height 21cm each .3608 cm^3 of metal is wasted .The remaining metal is used to make spherical balls of radius 21 cm Find the number of balls that can be madePlzz answer this question
Answer» Answer: 3 balls Step-by-step explanation: RADIUS of HEMISPHERE = 42 cm Vol. of hemisphere = $\frac{2}{3} \pi$ $r^{3}$ = 2/3 x 22/7 x 42 x 42 x 42 = 155232 cm cube Vol. of 4 cones = 4 x $\frac{1}{3} \pi r^{2} h$ = 4 x 1/3 x 22/7 x 20 x 20 x 21 = 8800 x 4 = 35200 cm cube Vol. remaining = 155232 - 35200 - 3608 (WASTED) = 116242 cm cube Vol. of balls = $\frac{4}{3} \pi r^{3}$ = 4/3 x 22/7 x 21 x 21 x 21 = 88 x 21 x 21 = 38808 cm cube No. of balls = 116424 / 38808 = 3 balls