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Opposite Outside Angles (having the same measure of angles)

An angle that lies on the outside and is opposite each other, for example:

∠1 = ∠7

∠2 = ∠8

Opposite and Opposite Angles

1. If two parallel lines are cut by another line, four pairs of opposite angles are formed which

are the same size.
2. If there are two parallel lines cut by another line, then the dimensions of the opposite

external angles formed are the same size.

3. If there are two parallel lines cut by another line, then the opposite interior angles formed
are the same size.

4. If there are two parallel lines cut by another line so that the sum of the interior angles on
one side is 180°.

Inner Angle

The angle that is inside and its position is on the same side. If you add them together, the

angles that are on the same side will form an angle of 180°. As an example:

∠3 + ∠6 = 180°

∠4 + ∠5 = 180°

Unilateral Outer Angel

An angle that lies on the outside and its position lies on the same side. If they add up, the

angles that are on the same side will form an angle of 180°. As an example:

∠1 + ∠8 = ∠180°

∠2 + ∠7 = ∠180°

Opposite angles (same size)

Is an angle whose positions are opposite to each other, in table 1. the opposite angles are:

∠1 = ∠3 ∠2 = ∠4

∠5 = ∠7 ∠6 = ∠8

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