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Chapter 4: Coordinate Geometry

# The Formulas

The coordinate geometry is not difficult. The best way to do well on the coordinate geometry is to know the formulas very well. Here we list the most commonly used formulas on coordinate geometry. By knowing these formulas, we guarantee you will do well on the coordinate geometry.

The Distance Formula: The distance d between P1(X1, Y1) and P2(X2, Y2) is given by the formula d=Ö (X2-X1)2 + (Y2-Y1)2 .

The Midpoint Formula: Given P(X1, Y1) and Q(X2, Y2), the coordinates (Xm, Ym) of M, the midpoint of PQ, are [(X1+X2)/2, (Y1+Y2)/2].

# Lines

When comes to determine a line on a coordinate system, it is important to know the slope of the line. The slope of a line is the difference between the Y-Coordinates divided by the difference between the X-Coordinates of the two points that are used to determine the line. So the equation for the slope of a line is (Y2-Y1)/(X2-X1). Here are some additional concepts about the slope of a line:

All segments of a non-vertical line have equal slopes.

The slope of a non-vertical line is the slope of any segment of the line.

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