Theorem Thursday 8 Flashcards
Parallelogram consecutive angles theorem
If a quadrilateral is a parallelogram then it’s consecutive angles are supplementary
Parallelogram opposite angles theorem
If a quadrilateral is a parallelogram then it’s opposite angles are congruent
Parallelogram opposite sides theorem
If a quadrilateral is a parallelogram then it’s opposite sides are congruent
Polygon exterior angles theorem
The sum of the measures of the exterior angles of a convex polygon one angle at each vertex is 360 degrees
Corollary to the polygon interior angles theorem
The sum of the measures of the interior angles of a quadrilateral is 360 degrees
Polygon interior angles theorem
The sum of the measures of the interior angles of a convex n-gon is (n-2)180
Parallelogram diagonals theorem
If a quadrilateral is a parallelogram, then it’s diagonals bisect each other
Parallelogram opposite sides converse
If both pairs of opposite sides of a quadrilateral are congruent then the quadrilateral is a parallelogram
Parallelogram opposite angles converse
If both pairs of opposite angles of a quadrilateral are congruent then the quadrilateral is a parallelogram
Opposite sides parallel and congruent theorem
If one pair of opposite sides of a quadrilateral are congruent and parallel then the quadrilateral is a parallelogram
Parallelogram diagonals converse
If the diagonals of a quadrilateral bisect each other then the quadrilateral is a parallelogram
Rhombus corollary
A quadrilateral is a rhombus if and only if it has 4 congruent sides
Rectangle corollary
A quadrilateral is a rectangle if and only if it has four right angles
Square corollary
A quadrilateral is a square if and only if it is a rhombus and a rectangle
Rhombus diagonals theorem
A parallelogram is a rhombus if and only if it’s diagonals are perpendicular
Rhombus opposite angles theorem
A parallelogram is a rhombus If and only if each diagonal bisects a pair of opposite angles
Rectangle diagonals theorem
A parallelogram is a rectangle if and only if it’s diagonals are congruent