geometry: chapter 5 Flashcards
Parallelogram
A quadrilateral with both pairs of opposite sides parallel
Quadrilateral
A four sided polygon
Theorem 5-1
Opposite sides of a parallelogram are congruent
Theorem 5-2
Opposite angles of a parallelogram are congruent
Theorem 5-3
Diagnose of a parallelogram bisect each other
Theorem 5-4
If both pairs of opposite sides of a quadrilateral are congruent then the quadrilateral is a parallelogram
Theorem 5-5
If one pair of opposite sides of a quadrilateral are both congruent and parallel than the quadrilateral is a parallelogram
Theorem 5-6
If both pairs of opposite sides of a quadrilateral are congruent than the quadrilateral is a parallelogram
Theorem 5-7
If the diagonals of a quadrilateral bisect each other than the quadrilateral is a parallelogram
Five ways to prove that a quadrilateral is a parallelogram
show that both pairs of opposite sides are parallel
Show that both pairs of opposite sides are congruent
Show that one pair of opposite sides are both congruent and parallel
Show that both pairs of opposite angles are congruent
Show that the diagonals bisect each other
Theorem 5-8
If two lines are parallel then all points on one line are equidistant from the other one
Theorem 5-9
If three parallel lines cut off congruent segments on one transversal then they cut off congruent segments on every transversal
Theorem 5-10
A line that contains the midpoint of one side of a triangle and is parallel to another side passes through the midpoint of the third side
Theorem 5-11
The segment that joins the midpoint of two sides of a triangle is
Parallel to the third side
Half as long is the third
Rectangle
A quadrilateral with four right angles