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Lesson 19 Polygons. Kalyani David. Objective. 1. Define polygon 2. Identify and describe polygons by the number of sides and angles 3. Explain the difference between regular and irregular polygons. What is a Polygon????. Any ideas? Write down what you think it is for . A polygon is….
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Lesson 19 Polygons Kalyani David
Objective 1. Define polygon2. Identify and describe polygons by the number of sides and angles3. Explain the difference between regular and irregular polygons
What is a Polygon???? Any ideas? Write down what you think it is for
A polygon is… a closed figure with three or more sides.
A polygon is a closed figure with 3 or more sides (all straight lines, no curves).
Check your work Polygon Not a polygon Not a polygon polygon polygon Not a polygon Not a polygon Polygon
Check your work Polygon polygon Not a polygon polygon Not a polygon Polygon Not a polygon Polygon
Essential Question Where do we see Polygons in our everyday Environment ?
Triangle • A triangle has three sides. 1 3 2
Quadrilateral • A Quadrilateral has four sides. 4 3 1 2
Pentagon • A pentagon has five sides. 1 5 2 4 3
Hexagon • A hexagon has six sides.
Heptagon • A heptagon has seven sides. heptagon
Octagon • An octagon has eight sides.
8 sided Polygon = Octagon Hint: “oct”opus – 8 legs
Classifying Polygons by number of Sides Q: What do we call a polygon with more than 12 sides? A : An ‘n’-gon where ‘n’ is the number of sides Ex: a 20 sided polygon is a 20-gon
Let’s Review: • The triangle is the smallest polygon. It only has three sides. • A pentagon has five sides. • A hexagon has six sides. • A heptagon has seven sides. • An octagon has eight sides.
Match these. Triangle eight sides Heptagon three sides Octagon seven sides
Match some more. Pentagon four sides Hexagon five sides Square six sides
Key Question: • A triangle is the smallest polygon because it has three sides. Can you have a two-sided polygon? Why or why not? Two lines don’t close to make a shape. They make an angle. 1 2
Practice set and Written Practicefrom your Text Page:123 Home Work