



 
Alan, I think we didn't get part of your attachment as we didn't see your solution, just the problem statement above and a diagram. I redrew the diagram you sent to have circles where the radii look like they are in the ratio of 1 to 3. I drew the line MP to be parallel to CA and I joined the centres of the circles. The line OM passes through the point of tangency of the circles (Do you see why?) so OM = 3 + 1 = 4 cm. Also PO = 3  1 = 2. Since MP is parallel to AC angle MPO is a right angle. Can you now see the length of MP? If not Pythagoras can help. This gives you AC = BD = PM. You can find the arc lengths you need if you can find the measures of the angles POM and OMP. Does you knowledge of the side lengths of the triangle POM tell you this? What is the cosine of the angle POM? I hope this helps, Penny  


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