Chapter 6 Flashcards
Polygon
a plane figure that is formed by three or more segments called sides.
consecutive vertices
two vertices that are the endpoints of the same side
diagonal
a segment that joins two nonconsecutive vertices of a polygon
Types of polygons
triangle, 3 sides quadrilateral, 4 sides Pentagon, 5 sides Hexagon, 6 sides Heptagon, 7 sides Octagon, 8 sides
Theorem 6.1 “Quadrilateral interior angles theorem”
The sum of the measures of the interior angles of a quadrilateral is 360`
parallelogram
a quadrilateral with both pairs of opposite sides parallel.
in ▱ABCD where A-B ll D-C and B-C ll A-D (both sides are congruent)
Theorem 6.2 “Quadrilateral parallelogram”
Congruent sides
If a quadrilateral is a parallelogram, then its opposite sides are congruent.
Theorem’s 6.3 and 6.4 “Quadrilateral parallelogram” congruent angles and supplementary angles
If a quadrilateral is a parallelogram, then its opposite angles are congruent
If a quadrilateral is a parallelogram, the its consecutive angles are supplementary
Theorem 6.5 “Quadrilateral parallelogram”
diagonals
If a quadrilateral is a parallelogram, then its diagonals bisect each other.
Theorem 6.6 “congruent sides converse”
Theorem 6.7 “converse of congruent angles”
If both pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a parallelogram
If both pairs of opposite angles of a quadrilateral are congruent , then the quadrilateral is a parallelogram.
Theorem 6.8 “converse of congruent angles”
supplementary
If an angel of a quadrilateral is supplementary to both of its consecutive angles, then the quadrilateral is a parallelogram
Theorem 6.9 “converse of diagonals”
If the diagonals of a quadrilateral bisect each other, then the quadrilateral is a parallelogram
rhombus
a parallelogram with four congruent sides
rectangle
a parallelogram with four right angles
square
a parallelogram with four congruent sides and four right angles
Corollaries
Rhombus Corollary: If a quadrilateral has four congruent sides, then it is a rhombus
Rectangle Corollary: If a quadrilateral has four right angles, then it is a rectangle.
Square corollary: If a quadrilateral has four congruent sides and four right angles, then it is a square.
Theorem 6.10 “rhombus diagonals”
The diagonals of a rhombus are perpendicular
Theorem 6.11 “rectangle diagonals”
The diagonals of a rectangle are congruent
Trapezoid
a quadrilateral with exactly one pair of parallel sides
the parallel sides are the bases
it also has two pairs of base angles and if the legs of a trapezoid are congruent, then the trapezoid is a isosceles trapezoid
Theorems 6.12 and 6.13
isosceles
If a trapezoid is isosceles, then each pair of base angles are congruent
If a trapezoid has a pair of congruent base angles, then it is isosceles
midsegment of a trapezoid
the segment that connects the midpoints of its legs.
mid. = 1/2(sum of the bases lengths