Engineering Mechanics - Center of Gravity and Centroid - Discussion

I need to find the centroid of the human body for both a standing and seated position as part of design that I am putting together for an adaptive wheelchair design for a handicapped individual.

If anybody can please explain to me how to go about finding the overall centroid of a seated and standing human being I would greatly appreciate it.
FROM Michael~S:

I am assuming that you just make an assumption that the limbs and torso can be approximated as rectangular sections, with the head approximated as a circle.

If someone can give me a quick calculation or run-through of how this would be done, I would greatly appreciate it.

Thanks for your assistance.

a1 = pixr^2 = pix25^2 = 1963.5;
a2 = 110 * 25 = 2750;
a3 = pixr^2 = pix12.5^2 = 491;
y1 = 25; y2 = 105; y3 = 172.5.

= (a1y1 + a2y2 + a3y3) / (a1 + a2 + a3) = 85mm.

@Thompson Victor.

y3 is measured from base to half of the top circle. i.e dia 25 mm so half means 12.5mm
therefore from base 172.5= 50+110+12.5.

My Answer does not match with the given options.

The correct answer is 81.19 please do check the calculations once again.

Does the centroid of individual sections match with the centroid of the built-up section?

Please explain.

The use of centroid is. It tells you at what point the given object is in equilibrium (balance).

However the nearest available option is 85.9 for 81.18. So we need select the option C.

According to me, the correct answer is 81.24mm.

I think 81.2 mm is the correct answer.

What is the centroid for human body?