In the triangle ABC, DM and en divide AC and BC vertically and equally, intersecting AB with m, N. if ∠ MCN = 48 °, then ∠ ACB =?
If DM divides AC vertically, then am = cm ∠ a = ∠ ACM. Similarly, ∠ B = ∠ BCM (1) m is close to a and N is close to B. at this time, ∠ ACM + ∠ MCN + ∠ BCM = ∠ ACB (∠ a + ∠ b) + 48 ° = ∠ ACB. Because ∠ ACB + (∠ a + ∠ b) = 180 ° the solution is: ∠ ACB = 114 ° (2) m is close to B and N is close to A. at this time, ∠ ACM - ∠ MCN + ∠ BCM = ∠ AC
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