1. The problem statement, all variables and given/known data The world’s largest ball of string is about 2 meter in radius. To the nearest order of magnitude, i.e., the power of ten, determine what is the total length of the 4mm diameter string in the ball? 2. Relevant equations 3. The attempt at a solution I calculated the volume of the ball "(considering it to be a sphere), using 2m as radius - After getting the value, I assumed the thread to be a "cylinder" and used "Cylinder's volume formula" --- V=Pie x R(squared) x H and calculated H .. Is that correct ?