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LM = AL + BM wanted, angle bisectors, ABCD

Source: 1990 Swedish Mathematical Competition p4

April 2, 2021
geometryangle bisectorequal segments

Problem Statement

ABCDABCD is a quadrilateral. The bisectors of A\angle A and B\angle B meet at EE. The line through EE parallel to CDCD meets ADAD at LL and BCBC at MM. Show that LM=AL+BMLM = AL + BM.