Three tangent circles of radius 10 cm are drawn. All centers lie on the line AB. The tangent AC to the right-hand circle is drawn, intersecting the middle circle at D and E. Find the length of the segment DE.
AQ = 50 AP = 30 CQ = 10
RP = (10 * 30) / 50 = 6
DE = 2[sqrt(102 - 62)] = 16
