Basic coordinate geometry
- Cartesian coordinates are simply the x-y coordinate system
- Straight line graphs are of the form y = mx + c
- m is the gradient
- c is the y-axis intercept
- Part of a straight line is called a line segment
How do I find the length of a line (segment)?
- By finding the distance, d, between two points (x1, y1) (x2, y2)
- Pythagoras’ Theorem (a2 = b2 + c2) is used to find the length of a line
How do I find the midpoint of a line (segment)?
- M is often used as the midpoint between two points (x1, y1) (x2, y2)
- It is the average of both the x and y coordinates
Exam Tip
Work with the square of a distance for as long as possible as this avoids early rounding errors and surds.Only square root when forced to or for a final answer, and use the ANS button (and other memory features) on your calculator.
Worked Example
