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Recommendation of junior high school geometric mathematics test paper
These topics study the transformation of graphics.

The first question has been answered very well upstairs.

2.?

As shown in the figure, triangle AFC and triangle ABE are folded along AF and AE respectively. Branch 1 ∠ 1 = ∠ 2 = 45.

Therefore ∠ fge = 90. So the triangle is a right triangle.

(If strict proof is required, it is as follows: Fold the triangular AFC along the AF into a triangular AFG. Connect GE.

It is proved that all triangles AEB are equal to triangles AEG. Then ∠ 1 = ∠ 2 = 45

Therefore ∠ fge = 90. Direct evidence.

3.

Rotate triangle ABC to triangle AEF as shown in the figure.

Judging from the meaning of the question, DC=DF=BC+EF= 1. DA=DA。

AC=AF again. Therefore, the triangular ADC is completely equal to the triangular ADF.

It doesn't look like it, but it is.

The area of triangle ADF is 1× 1 divided by 2= 1/2.

So the area of the hexagon is 1/2×2= 1.

Just a moment, please.