Constructing a perpendicular bisector using a compass and a ruler
1
Draw a line segment [AB]. Place the compass point at A. Use a compass setting that is greater than half of the length of [AB]. Draw an arc.
A B 2
2
Keep the same compass setting. Place the compass point at B. Draw an arc such that it intersects the fi rst arc at two points.
A 3
Draw a line through the two points of intersection.
A M B 4
Mark the right angle on the diagram. This line is the perpendicular bisector of [AB]. It passes through M, the midpoint of [AB]. Therefore, |AM| = |MB|
Worked example 4
State whether the following lines are parallel, perpendicular or neither. Give a reason for your answer and indicate how it is written in mathematical language (where possible).
(i) Z W X (iii) W X H Worked example 5
Using the map opposite, fi nd: (i) one street that is perpendicular to Hope Street (ii) one street that is parallel to Hope Street. In each case, give a reason for your answer.
Solution Z Y L O (ii) N M
Solution (i)
(ii) B
A
M
B
Section A Introducing concepts and building skills