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(10^{2} - 6^{2})] = 16