Day 11 Theorems

1
Day 11 Theorems

• Quadrilaterals

2

• Theorem If two lines are parallel, any point on
  one is equidistant from the other line.
• Given
• Prove EF CG.
• Use the given, and the def. of distance from a
  point to a line (along a perpendicular), we can
  conclude that CGFE is a parallelogram because of
  the shared perpendicular lines. Thus, EF CG
  because the opp. sides of a parallelogram are
  congruent.

3

• Choose A, B, C to maximize zeroes and minimize
  variables.
• Determine co-ordinates of D by using Midpoint
  Formula.
• AD
• by the Distance Formula
• CD
• BD
• (both by distance formula)
• AD BD CD (transitive)
• D is equidistant from A, B, C by definition

Given rt ?ABC D is midpoint of Prove D is
equidistant from A, B, C