Areas outside the overlapping circles indicated as shaded regions

Problem
From the figure shown, AB = diameter of circle O1 = 30 cm, BC = diameter of circle O2 = 40 cm, and AC = diameter of circle O3 = 50 cm. Find the shaded areas A1, A2, A3, and A4 and check that A1 + A2 + A3 = A4 as stated in the previous problem.
 

Circles with centers at midpoints of sides of a right triangle

 

Solution