Answer
10.885 kg
Work Step by Step
Take both the upper leg and lower leg together. Value in Table 7-1 gives us the relative mass of both legs so for value of only one leg, a factor of 1/2 have to be included. Assume a person's mass is 70 kg.
$$70kg\times\frac{(21.5+9.6)}{100}\times\frac{1}{2}=10.885kg$$