**Example 1:**
For the surface geometry shown, calculate the coordinates of the centroid and measured from the specified reference axes.

**Solution:** Although the shape shown is a simple
rectangle, it would be useful to see how we would calculate its centroid using
the integral equations. We solve this problem based on two different choices
for the differential area.

An alternative solution involves using a differential area of height *dy*
and width *dx.* In this case, we see double integrals in both numerator
and denominator of each equation. Also note that the centroid of the
differential area is at (x, y).