1. G RAPHING IN THE C OORDINATE P LANE Unit 10 7 th Grade Math By Jeff Clark

2. T HE N UMBER L INE

3. C ARTESIAN C OORDINATE S YSTEM In 1637 Rene Descartes developed this system while lying in bed looking at a fly on his ceiling.

4. A DDING ANOTHER DIMENSION Number LineCoordinate Plane

5. T HE C OORDINATE P LANE

6. C OORDINATES A coordinate is a location in the plane. It has an x value and a y value. In an ordered pair the x value is first, just like in the alphabet. Remember you’re a,b,c’s.( X, Y )

7. T WO POINTS MAKE A LINE One interesting problem is finding out how long a line segment is. If the points are on a line parallel to an axis, it is easy.

8. F INDING DISTANCE We can find the distance between two points by using a fact about right triangles. Remember the Pythagorean theorem?

9. R IGHT T RIANGLE The sum of the squares of both legs equals the square of the hypotenuse.

10. D ISTANCE FORMULA Where d equals the distance between the two points, we can use the pythagorean theorem to derive a formula to find the value of d.

11. E XAMPLE Distance AB is 3 Distance BC is 4 So distance AC is the square root of 3 squared plus 4 squared. 9 + 16 = 25, the square root of 25 is 5. Then distance AB is 5 units!