1. Chapter 7 Coordinate Geometry 7.1 Midpoint of the Line Joining Two Points 7.2 Areas of Triangles and Quadrilaterals 7.3 Parallel and Non-Parallel Lines 7.4 Perpendicular Lines

2. Coordinate Geometry Objectives 7.1 Midpoint of the Line Joining Two Points In this lesson, you will learn how to find the midpoint of a line segment and apply it to solve problems.

3. A line AB joins points (x 1, y 1 ) and (x 2, y 2 ). M (x, y) is the midpoint of AB. Construct a right angled triangle ABC. Construct the midpoints D and E of the line segments AC and BC. Take the mean of the coordinates at the endpoints. D is and E is M is the point Take the x-coordinate of D and the y-coordinate of E. Coordinate Geometry

4. P, Q, R and S are coordinates of a parallelogram and M is the midpoint of PR. Find the coordinates of M and S and show that PQRS is a rhombus. M is also the midpoint of QS. Coordinate Geometry Example 4

5. 3 points have coordinates A(–1, 6), B(3, 2) and C(–5, –4). Given that D and E are the midpoints of AB and AC respectively, calculate the midpoint and length of DE. Let M be the midpoint of DE. Coordinate Geometry Exercise 7.1, qn 3

6. Let M be the midpoint of AC. If A(2, 0), B(p, – 2), C(–1, 1) and D(3, r) are the vertices of a parallelogram ABCD, calculate the values of p and r. M is also the midpoint of BD. Coordinate Geometry Exercise 7.1, qn 4