the radius of the circle is 15, so its diameter is 30
that means the distance between P and M, and N and Q, is 30
because those distances are split up into three equal parts by the squares, each square has a length of 10
area of square = side^2
A = 10^2
A = 100
five squares:
100 * 5
500
the shaded area occupies 500 square centimeters