Kevin had to measure the diameter of a hair strand and the diameter of a grain of sand for his science experiment. He found the diameter of the hair strand to be 0.00006 inches and the diameter of a grain of sand to be 1.3 * 10-3 inches.

This is the concept of linear scale factors.

Diameter of hair strand is 0.00006=6*10^-5 inches

Diameter of sand grain is 1.3x10^-3 inches

Thus the the number of times the hair sand grain is bigger than hair strand will be:

linear scale factor = (diameter of sand grain) / (diameter of hair strand)

= (1.3*10^-3) / (6*10^-5)

=21 2/3 times