As shown in the figure, in ladder ABCD, ad ‖ BC, ab = DC, ∠ ABC = 72 °, now move waist AB to de in parallel, and then fold △ DCE along De to get △ DC ′ e, then the degree of ∠ EDC ′ is______ Degree

As shown in the figure, in ladder ABCD, ad ‖ BC, ab = DC, ∠ ABC = 72 °, now move waist AB to de in parallel, and then fold △ DCE along De to get △ DC ′ e, then the degree of ∠ EDC ′ is______ Degree

∵ parallel move waist AB to de, ∵ de = AB = CD, ∵ C = ∵ Dec = ∵ B = 72 °, ∵ EDC = 180 ° - 2 ∵ C = 36 ° according to the nature of folding, ∵ EC ′ d = ∵ C = 72 ° and ∵ EDC '= 180 ° - 2 ∵ EC ′ d = 36 °

As shown in the figure, in the quadrilateral ABCD, ∠ A and ∠ B complement each other, ∠ C = 90 °, de ⊥ AB, e is the perpendicular foot. If ∠ EDC = 60 °, calculate the degrees of ∠ B, ∠ A and ∠ ade

The ∵ A and ∵ B complement each other, that is ∵ a + ∵ B = 180 °, ∵ ad ∥ BC, ∵ ACD + ∵ ADC = 180 °, and ∵ de ⊥ AB, ∵ ADC = 90 °, ∵ ade = ∵ ADC - ∵ EDC = 90-60 = 30 °, ∵ in the right angle △ AED, ∵ a = 90-30 = 60 °,