At the end of this chapter you will be able to: Define polygon Chapter 17 Polygons At the end of this chapter you will be able to: Define polygon Measure angles Identify shapes such as quadrilaterals, rectangles, squares, parallelograms, and triangles Find perimeter of various polygons Find the area of various polygons Find the square root of numbers Words to Know Plane Figure A figure that has only length and width Polygon A plane figure with three or more sides Angle The space between two straight lines meeting at a point Degree The unit used to measure angles; the symbol for degree is Quadrilateral A plane figure with four sides Rectangle A plane figure with four sides and four ninety degree angles; the opposite sides of a rectangle are equal Square A plane figure with four equal sides and four ninety degree angles Parallel lines Lines that extend in the same direction at the same distance apart that never meet Parallelogram A plane figure with four sides; the opposite sides of a parallelogram are parallel What is this a picture of?? ______________________________

In this lesson, you will learn To identify figures as polygons Types of Polygons In this lesson, you will learn To identify figures as polygons To name polygons according to the number of sides Words to Learn Polygon: a closed ___________ formed by joining ____________ or more line segments at their endpoints Non-consecutive vertices: any two vertices that are not next to _______ another Diagonal: a line ____________ that joins two nonconsecutive vertices of a polygon Soccer balls are covered with geometric figures called _____________. How many different kinds of figures can you find on the soccer ball?____________________

Number of Sides Common Name Line segments form the sides of a polygon. Line segments have _________________. Number of Sides Common Name Triangle Octagon Quadrilateral Nonagon Pentagon Decagon Hexagon n-gon Heptagon Practice Name the sides, the vertices, and the diagonals of each polygon. W N X V Y M O U Z L P T S Sides:_____________________________ Sides:________________________________ Vertices:__________________________ Vertices:_____________________________ Diagonals:_________________________ Diagonals:____________________________

Sum of Interior Angles Formula 1: Sum of interior angles = (Number of sides – 2) x 180 = (5 – 2) x 180 = 3 x 180 = ____________ Practice ______- 2 x 180 ______ x 180 _________________ ______- 2 x 180 ______ x 180 _________________ ______- 2 x 180 ______ x 180 _________________

4 5 6 7 8 9 10 # of sides Sum of interior Angles ** Look through your notes from yesterday and the worksheet to fill in this chart. You will need it for todays activity.

Interior angle = sum of interior angle Number of sides ________________ 7 = Practice ______________ 4 = ______________ 5 = ______________ =

Find the Missing Interior Angle ******Use the reference sheet we created for the sum of the interior angles. If you do not have it use the formula (# of sides – 2) x 180 Sum of the interior angles = 120 + 140 + 130 + 150 + 88 + x 720 = ____________ + x

__________ = _________+ _________ + ________ + _________ + X

Perimeter of Polygons Perimeter- ___________ all sides 7 mm How many sides does this shape have?________________________________

# of sides * measurement 12 cm