As shown in the figure, in trapezoidal ABCD, ad ‖ BC, ∠ a = 90 °, e is the point above AB, EC = ed, ∠ BEC = 75 °, AED = 45 °, verification: ab = BC

As shown in the figure, in trapezoidal ABCD, ad ‖ BC, ∠ a = 90 °, e is the point above AB, EC = ed, ∠ BEC = 75 °, AED = 45 °, verification: ab = BC

It is proved that DF ⊥ BC and D point F are made,
,
In trapezoidal ABCD, ad ‖ BC, ∠ a = 90 °,
∴∠B=90°，
∵DF⊥BC，
∴∠DFB=∠DFC=90°，
The ABFD is a rectangle,
∴AB=DF．
∵∠BEC=75°，∠AED=45°，
∴∠DEC=60°，∠ECB=15°
Delta Dec is an equilateral triangle,
∴∠DCE=60°，DC=DE．
∠DCF=∠DCE+∠ECF=75°，
In △ BCE and △ FDC,
∠BEC＝∠FCD
∠B＝∠CFD
CE＝CD ，
∴△BCE≌△FDC（AAS），
BC=DF．
∴AB=BC．

As shown in the figure, a is parallel to B. if the right angle vertex of triangle plate is placed on the straight line B, foot 1 equals 40 degrees, then the degree of angle 2 is

60 degrees

As shown in the figure, a ‖ B, ∠ 1 = 70 °, 2 = 40 °, find ∠ 3

∵a∥b，
∴∠4=∠2=40°，
∵∠1+∠3+∠4=180°，∠1=70°，
∴∠3=70°．

Footprints of small animals

Do you need the pattern of small animal footprints refer to the hand footprints? We are specialized in making hand and foot prints of baby Zodiac. I don't know if it's what you need

As shown in the figure, in △ ABC, ∠ ACB = 90 °, CD ⊥ AB is in D, ∠ B = 40 °. Find out the degrees of ∠ A and ∠ ACD

∵∠ACB=90°，
∴∠A=90°-∠B=90°-40°=50°，
∵CD⊥AB，
∴∠ACD=90°-∠A=90°-50°=40°．

It is known that: as shown in the figure, ab ⊥ CD, the perpendicular foot is O, EF passes through the point O, ∠ 2 = 4 ∠ 1, and calculate the degrees of ∠ 2, ∠ 3, ∠ BOE

∵AB⊥CD，
∴∠1+∠2=90°，
And ∵ 2 = 4 ∠ 1,
The solution is ∠ 1 = 18 ° and ∠ 2 = 72 °,
Ψ 3 = 18 ° (the opposite vertex angle is equal),
∠BOE=180°-∠3=162°．

As shown in Figure 7-7, ∠ 1 = ∠ 2, ∠ 3 = ∠ 4, ∠ 5 = ∠ 6, then the degree of ∠ 7 is ∠ 1_______ Times Figure 7-7

Angle 3 = 2 angle 1 = angle 4
Angle 5 = 180 angle 2 - (180-4 angle 1) = 3 angle 1
Angle 7 = 180 angle 4 - (180-6 angle 1) = - 2 angle 1 + 6 angle 1 = 4 angle 1

Calculate the degree of ∠ 1 + ∠ 2 + ∠ 3 + ∠ 4 + ∠ 5 + ∠ 6 in figure 7-37 It's the question in new target detection. It's 13 on page 35

Man, you can't have what you call "new target detection". Even different schools use different teaching materials. You can paste the title directly, so that we can do the title directly. You can reply the question to me and I will help you solve it

As shown in the figure, ∠ 1 + ∠ 2 + ∠ 3 + ∠ 4 + ∠ 5 + ∠ 6 =?

∵∠7=∠1+∠5，∠8=∠4+∠6，
∴∠1+∠2+∠3+∠4+∠5+∠6=∠2+∠3+∠7+∠8=360°．
Therefore, 1 + ∠ 2 + ∠ 3 + ∠ 4 + ∠ 5 + ∠ 6 = 360 °

As shown in the figure, ∠ 1 + ∠ 2 + ∠ 3 + ∠ 4 + ∠ 5 + ∠ 6 + ∠ 7 = () degree A. 450 B. 540 C. 630 D. 720

As shown in the figure
∵∠3+∠4=∠8+∠9，
∴∠1+∠2+∠3+∠4+∠5+∠6+∠7，
=∠1+∠2+∠8+∠9+∠5+∠6+∠7，
=The sum of internal angles of Pentagon = 540 °,
Therefore, B