4 m = distance
You know that each revolution would be equal to the circumference of the ball.
Circumference = Pi * Diameter
where pi = 3.142
So then 4 m divided by 10 Revolution will tell us what one revolution equaled.
In this case 4/10= 0.4This is are circumference, 0.4 = 3.142*d
0.742625716 would be the diameter or 74.26 millimeters.