 # 6.1 Polygons Textbook page 303. Definitions A polygon is a plane figure that is formed by three or more segments called sides. (a closed, sided figure)

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6.1 Polygons Textbook page 303

Definitions A polygon is a plane figure that is formed by three or more segments called sides. (a closed, sided figure) Each side intersects exactly two other sides at each of its endpoints. Each endpoint is a vertex of the polygon. Two vertices that are endpoints of the same side are consecutive vertices. A segment that joins two nonconsecutive vertices of a polygon is called a diagonal. Vertices side diagonal Consecutive vertices

Is the figure a polygon? Why or why not? Yes, the figure is closed and formed by straight sides

Is the figure a polygon? Why or why not? No, one of the “sides” is not a segment – it is a curve

Is the figure a polygon? Why or why not? No, two of the sides only intersect one other side – it is not a closed figure

Is the figure a polygon? Why or why not? Yes, the figure is closed and formed by straight sides

Naming Polygons Number of SidesName of Polygon 3 4 5 6 7 8 9 10 12 n

Naming Polygons Number of SidesName of Polygon 3Triangle 4 5 6 7 8 9 10 12 n

Naming Polygons Number of SidesName of Polygon 3Triangle 4Quadrilateral 5 6 7 8 9 10 12 n

Naming Polygons Number of SidesName of Polygon 3Triangle 4Quadrilateral 5Pentagon 6 7 8 9 10 12 n

Naming Polygons Number of SidesName of Polygon 3Triangle 4Quadrilateral 5Pentagon 6Hexagon 7 8 9 10 12 n

Naming Polygons Number of SidesName of Polygon 3Triangle 4Quadrilateral 5Pentagon 6Hexagon 7Heptagon or Hectagon 8 9 10 12 n

Naming Polygons Number of SidesName of Polygon 3Triangle 4Quadrilateral 5Pentagon 6Hexagon 7Heptagon or Hectagon 8Octagon 9 10 12 n

Naming Polygons Number of SidesName of Polygon 3Triangle 4Quadrilateral 5Pentagon 6Hexagon 7Heptagon or Hectagon 8Octagon 9Nonagon 10 12 n

Naming Polygons Number of SidesName of Polygon 3Triangle 4Quadrilateral 5Pentagon 6Hexagon 7Heptagon or Hectagon 8Octagon 9Nonagon 10Decagon 12 n

Naming Polygons Number of SidesName of Polygon 3Triangle 4Quadrilateral 5Pentagon 6Hexagon 7Heptagon or Hectagon 8Octagon 9Nonagon 10Decagon 12Dodecagon n

Naming Polygons Number of SidesName of Polygon 3Triangle 4Quadrilateral 5Pentagon 6Hexagon 7Heptagon or Hectagon 8Octagon 9Nonagon 10Decagon 12Dodecagon nn-gon

Quadrilaterals Quadrilaterals are made of two triangles. The sum of the angles in a triangle is 180 o. 2 * 180 = 360 total 180 o

Quadrilateral Interior Angles Theorem The sum of the interior angles of a quadrilateral is 360 o. m<1 + m<2 + m<3 + m<4 = 360 o 4 1 3 2

Find the measure of <A 90 0 A B C D 110 0 60 0 100 0

Find the measure of <A 65 0 A B C D 55 0 80 0 160 0

Find the measure of <A 72 0 A B C D 108 0 72 0 108 0

Homework Assignment # 10 Textbook page 306 Problems 1-23, 30-42 You do not have to write the problems, but you MUST show your work on 6,7, 15-20, and 37-42

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