In this question we are asked to find the
distance of the centre of mass of a uniform
square of side length a from one of its corners.
A square has four lines of symmetry. The centre
of mass lies at the intersection of these
lines of symmetry. In this question, we want
to find the distance, let's call it d, from
one of the corners of the square to its centre
of mass. In terms of its side length, a. The
two distances shown are both a/2. We can now
use Pythagoras' theorem to calculate d in
terms of a.
