Year 9 Interactive Maths - Second Edition

Parallel Lines

Note:

Arrows are placed on the lines AB and CD to indicate that they are parallel.

A line that meets two or more parallel lines is called a transversal.  Line PQRS in the following diagram is a transversal.

• z and x (or u and v) are alternate angles
• x and y are corresponding angles
• u and x (or z and v) are allied or co-interior angles
• y and z are vertically opposite angles

Recall that:

• Alternate angles are always equal.
• Corresponding angles are always equal.
• Allied (or co-interior) angles are supplementary.
• Vertically opposite angles are always equal.

Example 6

Use the information given in the diagram to find:

a.  x
b.  y
c.  z
d.  u
e.  p

Solution:

Key Terms

parallel lines, transversal, alternate angles, corresponding angles, co-interior angles, vertically opposite angles, allied angles

Study Another Topic in Chapter 13: Geometry

[ Angle Facts of Geometry ] [ Parallel Lines ] [ Triangles ] [ Deductive Geometry ] [ Quadrilaterals ] [ Congruence ] [ Similar Triangles ] [ Geometric Constructions ] [ Bisector of an Angle ] [ Perpendicular Bisector of a Line Segment ] [ Perpendicular from a Point on to a Line ] [ Perpendicular at a Point on the Line ] [ Problem Solving Unit ] [ Symbols ] [ Index ]