Uploaded by moira kennedy

# Coordinate Geometry the line Key Words

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```Coordinate Geometry: The Line - Key words
Length/Distance/Radius/ |AB|
Midpoint/Centre/M
Slope/Rate of change/m
|AB|= √(๐ฅ2 − ๐ฅ1 )2 + (๐ฆ2 − ๐ฆ1 )2
๐ฆ1+๐ฆ
๐ฅ +๐ฅ
2
M= ( 1 2 ,
)∗
2
2
๐๐๐๐๐๐๐๐ ๐กโ๐๐  ๐๐  ๐ ๐๐๐๐๐ก(๐, ๐)
(a) y=mx+c … when given an equation- Get y by
itself
๐๐๐ ๐
(b) m= ๐๐ข๐ …….. When given a graph
๐ฆ −๐ฆ
(c) m=๐ฅ2 −๐ฅ1 …. when given coordinates
2
Parallel
Perpendicular
Equation of a line
Intercepts
Point of intersection
Area of Triangle
1
Parallel lines have equal slopes … m1=m2
Perpendicular lines have opposite slopes (turn
upside down and change the sign)
To prove lines are perpendicular m1&times;m2=-1
(a) y=mx+c ….. slope and intercept
(b) ๐ฆ − ๐ฆ1 = ๐(๐ฅ − ๐ฅ1 ) …. point and slope
Where cuts the x-axis: Let y=0
Where cuts the y-axis: Let x=0
Simultaneous Equations - find x and go back to find
y
1
(a) 2 ๐ &times; ๐ป…right angled
1
(b)2 ๐๐๐ ๐๐๐ถ … . ๐ด๐๐๐๐ ๐๐ข๐ ๐ก ๐๐ ๐๐๐ก๐ค๐๐๐ ๐ก๐ค๐ ๐ ๐๐๐๐
1
(c) 2 |๐ฅ1 ๐ฆ2 − ๐ฅ2 ๐ฆ1 | …
๐๐๐ฃ๐๐ ๐๐๐๐๐๐๐๐๐ก๐๐  . . ๐๐๐ ๐๐๐๐๐ก ๐๐ข๐ ๐ก ๐๐ (0,0)
```