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Shape, Space and Measure (Intermediate) - Angles on Parallel Lines
 
Alternate Angles | Corresponding Angles | Interior Angles
Alternate Angles

Alternate angles are equal and pairs of them are shown in the diagram below.
They form a Z shape.

Angle c = Angle b (Alternate Angles)

Angle a = Angle d (Alternate Angles)
angles on parallel lines1

Corresponding Angles

Corresponding angles are equal and pairs of them are shown in the diagram below.
angles on parallel lines2
Angle b = Angle d (corresponding angles)

Angle a = Angle c (corresponding angles)

These are above the parallel lines and there are two more below, unlabelled. They form an F shape.
 

Interior Angles
 
These are on the inside of the parallel lines as shown below.
angles on parallel lines3
Interior angles add up to 180o .
angles on parallel lines4
Again these properties can be used to solve problems.
 
For Example:
In the diagram below calculate angles a, b, c and d.
 
angles on parallel lines5
angles on parallel lines6