1. 2.1 - 1 The Rectangular Coordinate System Quadrant I Quadrant II Quadrant III Quadrant IV 0 x-axis y-axis a b P(a, b)

2. 2.1 - 2 The Distance Formula Note Suppose that P(x 1, y 1 ) and R(x 2, y 2 ) are two points in a coordinate plane. Then the distance between P and R, written d(P, R) is given by

3. 2.1 - 3 Example 2 USING THE DISTANCE FORMULA Solution: Find the distance between P(– 8, 4) and Q(3, – 2.) Be careful when subtracting a negative number.

4. 2.1 - 4 Midpoint Formula The midpoint of the line segment with endpoints (x 1, y 1 ) and (x 2, y 2 ) has coordinates

5. 2.1 - 5 Example 5 USING THE MIDPOINT FORMULA Use the midpoint formula to determine the following. Solution a. Find the coordinates of M of the segment with endpoints (8, – 4) and (– 6,1). Substitute in the midpoint formula.