Polygons Triangles and Quadrilaterals

What is a polygon? Closed figure At least 3 sides Line segments are sides Sides meet is call a vertex

More Polygon Terms Diagonal – connects two non consecutive vertices Concave – at least one diagonal outside polygon, dented in Convex – no diagonals outside polygon Perimeter – distance around polygon Area – space polygon covers up

Define these types of Polygons pg 56 Equilateral Equiangular Regular All the sides of the polygon are congruent All the interior angles of the polygon are congruent All sides are congruent and all angles are congruent

Types and prop of polygons name sides sum of interior angles measure of each interior angle if regular polygon sum of exterior angles measure of each exterior angle if a regular poygon number of diagonals Triangles Quadrilater al Pentagon Hexagon Heptagon Octagon Nonagon Decagon Undecagon Dodecagon N-agon namesides sum of interior angles measure of each interior angle if regular polygon sum of exterior angles measure of each exterior angle if a regular poygon number of diagonals Triangles Quadrilateral Pentagon Hexagon Heptagon Octagon Nonagon Decagon Undecagon Dodecagon N-agon N180(n-3)sum/n360360/nn(n-3)/2

Triangles – define the following pg 60 Right Acute Obtuse Notice the names of all these triangles deal with the type(s) of angle the triangle has Has only one right angle All 3 angles are acute angles Has only one obtuse angle In some case why can it have only one of that type of angle? Triangles interior angles add up to 180 and has 3 angles, if it had 2 right angles it is already at 180 and if it had 2 obtuse angles it would be over 180

More triangles pg 61 Scalene Isosceles Equilateral No sides congruent 2 congruent sides, also has two congruent base angles All sides are congruent When naming a triangle you need to use both the name for type of angle and number of congruent sides Notice all these triangles are named based on sides congruent

Classify vs Naming Classify is what we use the angles and sides for Naming we use the vertices of the triangle Naming Polygons you need to go in order of vertices – either clockwise or counter clockwise, you can not skip over a vertex Consecutive vertices means one right after the other

Congruent Polygons Polygons can be congruent but corresponding parts need to be congruent Corresponding – same location in the two polygons Congruent angles and sides Congruency Statement – name the polygons congruent in the correct order of congruent vertices

Examples Naming and Congruency Statements

Quadrilaterals define and list properties pg 64 Parallelogram Rectangle 2 pairs of parallel sides Opposite sides congruent Opposite angles congruent Consecutive angles supplementary Diagonals All properties of a parallelogram and All angles 90 degrees

Rhombus Square Trapezoid Kite All properties of a parallelogram and all sides congruent All properties of a parallelogram and all sides congruent and all angles 90 degrees 1 pair of parallel sides, there are 3 types we will discuss later 2 pairs of congruent consecutive sides, 1 pair of congruent angles

Quadrilaterals We will go into more depth with these shapes and come up with some additional properties as well

Homework Due by end of class Wkst Aliens Wkst Airlines In your notes Pg 57 15,16,17 Pg and 16 Pg 66 9 and 10