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Math and geometry problems in the first grade! 100 points!
I. as shown in figure 1, AB‖CD, ∠ 1=∠2, ∠3=∠4, verification: BC=AB+CD.

Second, as shown in Figure 2, ∠ ABC = 54, ∠ BAC = 70, BE and AD are the heights of △ABC, and H is the intersection of BE and AD, so find the degree of ∠BHA.

Question 1: Take a little f from BC, make BF=AB, connect e f, and it is easy to prove △ BFE △ BAE, ∴∠ AEB = ∠ FEB...① Again? ∠ 1+∠ 2+∠ 3+∠ 4 = 180, while ∠ 1=∠2, ∠3=∠4, ∠.