If AB=2, what are BD, AD, AC and BC respectively?

It is easy to know that ABD is an isosceles right triangle from the drawing process 1.

The key to this problem is that the intercept DE=DB on DA, which means that e is on the vertical line of BD (the distance from any point on the vertical line to both ends of the line segment is equal). Similarly, the intersection of AB and the vertical line in AE can get point C.

( 1)BD=AB= 1

Ad 2 = AB 2+BD 2, therefore, AD= root number 2.

ABD is an isosceles perspective triangle. From the drawing process, the vertical line in BD is parallel to AB, and the vertical line passes through the midpoint, so we can know that E is the midpoint of AD, and similarly, C is the midpoint of AB.

AC= 1/2AB= 1/2=BC

(2)C is the midpoint of AB, not the golden section.

The golden section is (root number 5- 1)/2, eh, how do you come out?

Painting a five-pointed star will have a golden section.