Answer
74.964 cm
Work Step by Step
A waist circumference that is at the 10th percentile is greater than 10% of all waist circumferences.
10% = 0.1
First, let's find a z-score so that the area of the standard normal curve to the left of this z-score is equal to 0.1.
According to the Table V, the z-score which gives the closest value to 0.1 is -1.28.
$z=\frac{X-μ}{σ}$
$-1.28=\frac{X-92.5}{13.7}$
$-1.28\times13.7=X-92.5$
$-17.536=X-92.5$
$X=-17.536+92.5=74.964$
