Vertical (forming four 90-degree angles)

Isomorphism angles of intersecting straight lines (on the same side of two straight lines and on the same side of a straight line)

Internal dislocation angle (above and below two truncated straight lines, on both sides of the truncated straight lines)

Inner angle of the same side (intersection of upper and lower straight lines, parallel lines and one side of the straight line)

After passing a point outside the straight line, there is one and only one straight line parallel to this straight line.

Two lines parallel to the same line are parallel to each other.

The isosceles angles are equal and the two straight lines are parallel.

Internal dislocation angles are equal and two straight lines are parallel.

Parallel lines and lateral internal angles are complementary and are two straight lines.

In the same plane, two straight lines perpendicular to the same straight line are parallel to each other.

Two straight lines are parallel and have the same angle.

Two straight lines are parallel and have equal internal angles.

These two lines are parallel and complementary.

A statement that judges a thing is called a proposition.

Translation moves the whole eye of a figure in a straight line direction, and a new figure will be obtained, which is exactly the same as the original figure in shape and size. Every point in the new graph is obtained by moving a point in the original graph. These two points are corresponding points, and the line segments connecting each group of corresponding points are parallel and equal. This movement of graphics is called translation transformation, or translation for short.

The above is the knowledge structure, key points and difficulties.

Main contents: parallel lines, three lines and octagons at the intersection of adjacent complementary angles and vertex angles and their judgment and translation.