As shown in the figure, the angle B = ∠ C = 90 °, M is a point on BC, and DM bisects ∠ ADC, am bisects ∠ DAB, proving: ad = CD + ab

As shown in the figure, the angle B = ∠ C = 90 °, M is a point on BC, and DM bisects ∠ ADC, am bisects ∠ DAB, proving: ad = CD + ab

It is proved that if Mn ⊥ ad is made in D, then ⊥ anm = b = 90 ﹥ 186; BAM = Nam [am bisection ﹥ DAB] am = am ﹥ ABM ≌ anm (AAS) ﹥ AB = an ⊥ NDM = CDM [DM bisection ﹥ ADC] ﹥ DNM = C = 90 ﹥ 186; DM = DM ﹥ DNM ≌ DCM (AAS) ﹥ nd = CD ﹥ ad = Nd + an = CD + ab