# Centroid of a C-Shape

nobodyuknow

## Homework Statement

http://prntscr.com/fcbm8

Find the centroid - All dimensions are in mm

## Homework Equations

xbar = (A1X1+A2X2) / (A1+A2)

Similarly for Ybar I assume

## The Attempt at a Solution

I got the y co-ordinate to be 20.428mm, and would assume that the x coordinate would be 5mm.

Is this right?

Homework Helper
Gold Member
You can divide the shape into three rectangular parts several different ways but I used two vertical lines in the obvious places. I assumed the origin is in the bottom left corner.

xbar = (A1X1+A2X2+A3X3) / (A1+A2+A3)

= (700*5 + 800*30 +400*30) / (700+800+400)
= 20.789

ybar = (A1Y1+A2Y2+A3Y3) / (A1+A2+A3)

= (700*35 + 800*10 + 400*65) / (700+800+400)
= 30.789

nobodyuknow
This is what confused me, does this mean the centroid is not on the shape itself?

Homework Helper
Gold Member
In this case yes. Where would the centroid of a doughnut be?