Question

the outer diameter of a metal ring is 14 cm and the inner diameter is 7 cm. If the ring has to be polished on both sides, what is the area to be polished?Also calculate the cost of polishing at Rs.8 per sq. cm.(pie =22/7)​

Answer 1

volume of a sphere (ring)=4/3pie r 3

4/3 x 22/7 x 3.5 x 3.5 x 3.5

4/3 × 22 x 0.5 x 3.5 x 3.5

4/3 x 22 x 42.875

1275.46