6. How to Construct a
Coordinate Proof:
ï Draw
and label a coordinate diagram
ï List given information
ï State what you will prove
ï Use given info to add to the diagram
ï Use algebra to prove statement
ï Write conclusion:
⊠âTherefore, blah = blah.â
7. Common Methods to use:
ï To
prove:
ï Segments are equal ï use distance
formula
ï Lines are parallel ï show slopes are
equal
ï Lines are perpendicular ï show slopes
multiply to -1
ï Segments bisect ï show they have the
same midpoint
ï Lines are concurrent ï show equations
have a common solution
8. Example 1:
ï Prove
that the midpoint of the
hypotenuse of a right triangle is
equidistant from the three vertices.
9. Example 2:
ï Prove
that the median of a trapezoid
is parallel to the bases and has
length equal to the average length
of the bases.