Archimedes deformation formula for eighth grade physics. V =?

Archimedes deformation formula for eighth grade physics. V =?

In the following figure, ∠ 1 and ∠ 2 are opposite to the vertex angle ()
A. B. C. D.

A. In B and C, both sides of ∠ 1 and ∠ 2 are not opposite extension lines to each other, so they are not opposite vertex angle, only C is opposite vertex angle

Two equal angles are opposite vertex angles. Is that right

Wrong
The same position angle is also equal

If two angles are not equal, they must not be opposite to the vertex,
Right or wrong! Controversial

This judgment is correct
reason:
The converse proposition of this proposition is: if two angles are opposite vertex angles, then they are equal [true proposition]
So this proposition is correct

Two unequal angles are not necessarily opposite vertex, right or wrong

Wrong. Because it's not precise
It should be said that two unequal angles must not be opposite vertex angles

Is the equivalent angle true or false to the vertex angle? If it is false, please give an anti column!

False proposition. The two angles of an isosceles triangle are equal, but not opposite to the vertex

Statement proposition: equal angle is opposite vertex angle. It is false proposition

Draw a bisector of an angle to show that the two new angles are equal, but they are not opposite to the vertex angle

It is proved that the proposition "equal to vertex angle" is true

Draw two straight lines at will to make them intersect
Let one pair of vertex angles be angle 1 and angle 2
The other pair of apex angle is angle 3 and angle 4
Because angle 1 + angle 3 = 180
Angle 2 + angle 3 = 180 (similarly)
SO 2 = 1
So it's equal to the vertex angle
Hope to help you!

Two equal angles are opposite vertex angles. Are they propositions

It's a proposition
However, this is a false proposition

How many pairs of vertex angles can 2009 straight lines intersect at one point

The combination formula should be used to calculate 2 * 2c2009 = 2009 * 2008 / 2 * 2 = 2009 * 2008