Angle of slope and angle between lines

Learning Objectives: By the end of the lesson, students should be able to calculate the angle of slope and angle between two lines.

Reference Materials:  New Further Mathematics Project 2 by M. R Tuttuh Adegun

Previous Knowledge: Students can draw the graph of a linear equation (straight-line graph).

Instructional Materials: Graph board and graph book.

Content:                                            

ANGLE OF SLOPE

Example:      Find the gradient of the line joining (3, 2) and (7, 10) and the angle of slope of the line.

Solution

Let m be the gradient of the line, then

m = (10-2)/(7-3) = 8/4 = 2

Let θ be the angle of slope of the line; then:

                                tanθ=2

                                θ=63.43°

ANGLE BETWEEN TWO LINES

EQUATION OF A LINE

The equation of a straight line is given by:          y =mx + c