1. Subject : Mathematics
Form : Two
Topic : Loci in Two Dimensions.
Duration : 60 Minutes
Learning Objective : Understand the concept of two dimensional loci.
Learning Outcomes : i. Describe and sketch the locus of a moving object.
ii. Determine the locus of points that are of
a) Constant distance from a fixed point
b) Equidistant from two fixed points
c) Constant distance from a straight line
d) Equidistant from two intersecting lines.
iii. Construct the locus of a set of all points that satisfies the condition:
a) The point is at a constant distance from a fixed point
b) The point is at equidistant from two fixed points
c) The point is at a constant distance from a straight line
d) The point is at equidistant from two intersecting lines.
Prerequisite knowledge : Students have already can perform constructions using straight edge
(ruler and set square) and compass.
Approach : Cooperative Learning
Moral Value : Fair, carefully, being cooperative
Resource : Worksheets, Power Point, text book, a pair of compasses, ruler, pencil.
2. Induction Sets
( 5 minutes)
1) Teacher asks 4 students to come in front.
2) All of 4 students are given 1 card each. Each student need to construct:
- a circle, given certain radius,
- a perpendicular bisector,
- a parallel lines and,
- an angle bisector.
3) Teacher discusses the answer with the student.
Procedure 2
( 10 minutes)
1) Teacher explains what a locus is.
2) Teacher ask student to sit in their group. Students work in their group. Each
group is given worksheet 1.
3) Teacher observes the student while they are discussing.
4) Teacher and students discuss the answers. Teacher asks the answer from one
student from each group.
5) Students make conclusion on the activity.
6) Teacher asks student to do the exercises 9.1A and 9.1B as a homework.
7) Teacher explains the lesson for today.
8) Teacher asks student to takes note how to determine the locus of a moving
point.
- the point is at a constant distance from a fixed point.
- the point is equidistant from two fixed point.
- the point is at a constant distance from a straight line.
- the point is equidistant from two intersecting lines.
Procedure 3
( 40 minutes)
1) Students work in their group. Each group is given worksheet 2.
2) Teacher asks students to construct
a) The locus of point which is at a constant distance from a fixed point.
Step 1 – describe or sketch the locus.
Step 2 – decide on a suitable scale
Step 3 - construct the locus accurately
i) Place a pair of compasses on a ruler to measure a distance of 1.5 cm.
ii) With the point pupil B as centre, draw an arc 1.5 cm from B to form a circle.
iii) This is the locus of pupil A.
b) The locus of point which is equidistant from two fixed point.
i) Set your compasses to a length more than half of XY. Place the point of your
compasses at X and draw an arc above and below the line.
ii) With the same length, place the point of your compasses at Y and draw two
