Question

试说明角A＋角B＝角C＋角D＋角E＋角F

Answer 1

连结CD, 有

A + B = 180 - AMB = 180 - CMD = MCD + MDC = (MCN + NCD) + (MDN + NDC) = (NCD + NDC) + (MCN + MDN) = (180 - CND) + (MCN + MDN) = (180 - ENF) + (MCN + MDN) = (E + F) + (C + D)