Answer
$13.7\%$ out of the human body
Work Step by Step
Again, we need to calculate the y value of the center of mass assuming the position of the upper legs to be 0.
Lets assume a right triangle is formed with the body from the hip to shoulder joint is the hypotenuse and is $15^o$ below the line from the hip to the knee joint. Then, the height of the triangle is $opp=x\sin(\theta)$ where x is the distance between hip and shoulder joint. $opp=(81.2m-52.1m)\sin(15^o)=7.53m$
$\frac{(21.5kg)(0m)+(9.6kg)(28.5m-18.2m)+(3.4kg)(28.5m-4.0m)+(6.6kg)(81.2m-71.7m+7.53m)+(4.2kg)(81.2m-55.3m+7.53m)+(1.7kg)(81.2m-43.1m+7.53m)+(6.9kg)((91.2-52.1)\sin(15.0^o)+7.53m)}{21.5kg+9.6kg+3.4kg+6.6kg+4.2kg+1.7kg+6.9kg}=13.7\%$out of the human body
