Construction – SS3 Mathematics Lesson Note (Second Term)

Instructional objectives: At the end of the lesson, the students should be able to:

• Definition of loci;
• State types of loci;
• Construct each type of loci; 
• Measure lines and angles correctly.

Instructional resource: Mathematical set.

Presentation.

Step 1: Identification of students’ prior ideas.

Mode: whole class.

Teacher’s activities: Explains the meaning of locus.

The locus of a point is the path traced by that point under a specific condition(s). The plural of locus is loci. It could be the distance from a point, a line, two points etc.

Students’ activities: note down the points.

Step 2: Exploration.

Mode: whole class.

Teacher’s activities: Lead the students in constructing the conditions.

1. Locus of point equidistant from a point: This is the circumference of a circle with the point as the centre. For example; draw a locus 2cm which is from a fixed point.

  Students’ activities: 

Construct the same in their books.

Step 3: Discussion.

Mode: whole class.

Teacher’s activities: Lead the students in constructing 2nd and 3rd conditions.

2. Locus of point equidistant from a line: This is the bisection of a line segment. For example; construct the locus of a point equidistant from line |AB|= 7cm.

3. Locus of points equidistant from two intersecting straight lines: This is the pair of bisectors of the angles formed by the two lines.

Students’ activities: construct the same in their books.

Step 4: Application.

Mode: whole class.

Teacher’s activities: Lead the students in constructing the last condition.

1. Locus of point equidistant from a given straight line: These are two parallel lines, one on each side of the given line. Example; construct the locus of point 3.2cm equidistant from line |AB|.

Students’ activities: construct the same in their books.

Step 5: Evaluation.

Mode: whole class.

Teacher’s activities: asks the students the following questions:

1. Define loci.
2. What is the meaning of the locus of two points?
3. Construct the locus of a point 3 cm from a given point.

Students’ activities: respond positively to the questions.

Assignment:

• Construct a circle with a triangle inside.

References:

• New General Mathematics for SS 1 by J B Channon et al.
• New Concept Mathematics for SS 1 by H N Odogwu et al.