Chapter 8: Quadrilaterals Flashcards
Theorem 30: The sum of the measures of the angles of a quadrilateral is
360
Definition 42: A quadrilateral is
a polygon that has four sides
Theorem 31: The length of a line segment drawn from any vertex of an equilateral triangle to a point on the opposite side is
less than the length of any side of the triangle
Definition 43: A trapezoid is_________________. The parallel sides are called_________ and the non parallel sides are called _______.
is a quadrilateral which has exactly one pair of parallel sides; bases; legs
Definition 44: An isosceles trapezoid is
a trapezoid that has both legs congruent.
Theorem 32: The lower (and upper) base angles of an isosceles trapezoid are
congruent
Theorem 33: The diagonals of an isosceles trapezoid are
congruent
Definition 45: A parallelogram is
a quadrilateral that has both pairs of opposite sides parallel
Theorem 34: If a quadrilateral is a parallelogram, then
pairs of consecutive angles are supplementary
Theorem 35: If a quadrilateral is a parallelogram, then
both pairs of opposite angles are congruent
Theorem 36: If a quadrilateral is a parallelogram, then
both pairs of opposite sides are congruent
Theorem 37: If a quadrilateral is a parallelogram, then
the diagonals bisect each other
Theorem 38: If both pairs of opposite angles are congruent, then
a quadrilateral is a parallelogram
Theorem 39: If both pairs of opposite sides are congruent, then
a quadrilateral is a parallelogram
Theorem 40: If one pair of opposite sides is both parallel and congruent (equal), then
a quadrilateral is a parallelogram
Theorem 41: If the diagonals bisect each other, then
a quadrilateral is a parallelogram
Theorem 42: The line segment joining the midpoints of two sides of a triangle is
parallel to the third side and is one-half its length
Definition 46: A rectangle is
a parallelogram with four right angles
Definition 47: A rhombus is
a parallelogram with four congruent sides
Definition 48: A square is
a parallelogram with four congruent sides and four congruent (right) angles
Theorem 43: The diagonals of a rectangle are
congruent
Theorem 44: The diagonals of a rhombus are
perpendicular to each other
Theorem 45: The diagonals of a rhombus bisect
the angles at the vertices which they join
