Answer
The distance from his feet to his center of gravity is 90.5cm
Work Step by Step
Let x be the distance from his feet to his center of gravity.
We are given that the weight of the person is $35.1kg+31.6kg=66.7kg$
Now we sum the torques about the scale on the right to solve for x.
$(+ \circlearrowleft) \sum \tau=0$
$-35.1kg*g*1.72m+66.7kg*g*x=0$
$-35.1kg*1.72m+66.7kg*x=0$
$x=\frac{35.1kg*1.72m}{66.7kg}$
$x\approx.905m$ or $90.5cm$
The distance from his feet to his center of gravity is 90.5cm