 Hello and welcome to the session. My name is Asha and I shall be helping you with the following question which says, find the amount of water displaced by a solid spherical ball of diameter first is 28 cm and second is 0.21 meters. So first let us learn the formula to calculate the volume of a sphere having radius r units. This is given by 4 upon 3 into pi into r cube. So with the help of this formula we are going to solve the above problem. So this is our key idea. Let us now start with the solution and first is 28 cm. So this is the diameter of the ball given to us. Now we have to find the amount of water displaced by the solid spherical ball of diameter 28 cm that is we have to find the volume of the ball having diameter 28 cm. So this implies radius is equal to 28 cm divided by 2 that is diameter upon 2 and this is equal to 14 cm. Now let us calculate the volume. The volume is given by 4 upon 3 into pi into r cube that is we have 4 upon 3 value of pi is 22 upon 7. Here r is the radius and radius is 14 cm so we have 14 into 14 into 14 and volume is given in units cube so we have 14 cm cube and on simplifying this we get 3, 4, 4, 9, 6 upon 3 cm cube or 11498 then 2 upon 3 cm cube. Hence the amount of water displaced by a ball of diameter 28 cm is 11498 then 2 upon 3 cm cube. So this completes the first part and now proceeding on to the second part and here the diameter is equal to 0.21 meters. So this implies its radius, let us denote it by small r is equal to 0.21 upon 2 meters that is 21 upon 200 meters. Now let us calculate the volume. So volume is equal to 4 upon 3 into pi into r cube that is 4 upon 3 into 22 upon 7 into 21 upon 200 into 21 upon 200 into 21 upon 200 meters cube and on simplifying this further we get 0.004851 meters cube. Hence the water that is displaced by a solid spherical ball of diameter 0.21 meters is 0.004851 meters cube. This completes the session. Bye and take care.