Formulae & Quick Help for Coordinate Geometry 

Distance formula 
Midpoint = 
Area of Triangle 
Slope of line = m

Finding the slope of a line from the
equation Y = MX + C 
All parallel lines have same slope 
To find a perpendicular slope you must flip and change sign eg 1/2 would have a perpendicular slope of 2/1.  To verify lines are perpendicular multiply their slopes together and you should get 1 i.e. m_{1}* m_{2 }= 1 
Equation of a line when you have slope and a point y  y_{1}= m(x  x_{1})  