find the cosine of the angle formed with the coordinates (-6, 7) located in standard position
Plot the point (-6,7)
 Draw the radius vector, r, from the origin (0,0) to the point (-6,7).
Draw the radius vector, r, from the origin (0,0) to the point (-6,7). 
 Indicate the angle.  I'll call it
Indicate the angle.  I'll call it  .
.
 Draw a vertical line perpendicular down to the x-axis, and
label it
Draw a vertical line perpendicular down to the x-axis, and
label it  .
.
 Draw a horizontal line from the origin to the bottom of
that line, completing a right triangle.  Label it
Draw a horizontal line from the origin to the bottom of
that line, completing a right triangle.  Label it  
 Now we find the length of
Now we find the length of  by the Pythagorean theorem:
 by the Pythagorean theorem:
 
 
 
 
 So we put
So we put  for
 for  :
: 
 Now since
Now since
 
 
 Edwin
Edwin