In order to figure out how big a ping pong ball is in inches, it would be best first to find out what size a ping pong ball is normally. The average diameter of a ping pong ball is 2 1/4 inches (5.715 cm), or about 5 3/4 inch (14.605 cm) in circumference.
Next, you can determine how many inches there are in 5 3/4 inch (14.605 cm) circumference by multiplying 14.605 by 6 and dividing the total by 12: 6(14.605cm)=84cm 84cm=5inches (12 inches=1 foot, therefore 6 inches=3/4 of one foot).
So now we know that the circumference is 5 inches. If we divide 5 by 3, we can get the diameter in inches:
5/3=1.666~ 1.67 inches
From this result, it can be safely concluded that a ping pong ball is about 1.7 inches in diameter on average.