plane figures sol5.13 ges mrs. norman. which shapes are polygons? why? polygonsnot polygons
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Plane Figures
SOL5.13GESMrs. Norman
Which Shapes Are Polygons? Why?
Polygons Not Polygons
What is a Polygon?
• A polygon is a closed plane figure made up of line segments.
• The names of common polygons tell how many sides the polygon has.
Triangle(3 sides)
Hexagon(6 sides)
Pentagon(5 sides)
Quadrilateral(4 sides)
vertex
side
Octagon(8 sides)
4
4
4
3
3
3 3
3
3
3
3
22
2
22 2
2
2
Plane Geometric Figures
A polygon is a closed plane figure with straight sides.
A regular polygon has congruent sides.congruent the same size and shape
Bees love Hexagons
QuadrilateralsTrapezoidExactly 1 pairof parallelsides
Parallelogram2 pairs of parallelsides
RhombusAll sides congruent
RectangleRight angles
SquareKite2 pairs of adjacent
congruent sides1 pair of congruent angles
QuadrilateralsTrapezoidExactly 1 pairof parallelsides
Parallelogram2 pairs of parallelsides
RhombusAll sides congruent
RectangleRight angles
SquareKite2 pairs of adjacent
congruent sides1 pair of congruent angles
Describe and Compare Polygons:
Sort polygons by their properties athttp://illuminations.nctm.org/
ActivityDetail.aspx?ID=34
Go to this site to make shapes with a virtual geoboard!http://matti.usu.edu/nlvm/nav/frames_asid_129_g_3_t_3.html
If you annotate over the desktop with ActiveInspire you can measure their sides and angles!
Adding Angles of Polygons
http://illuminations.nctm.org/ActivityDetail.aspx?ID=9
The angles of a triangle add to….
The angles of a quadrilateral add to….
Now explore further with this NCTM game:
What is a Regular Polygon?
• Clue: What do these polygons have in common?• A regular polygon has sides of equal length
and angles of equal measure
Triangle(3 sides)
Octagon(8 sides)
Hexagon(6 sides)
Pentagon(5 sides)
Quadrilateral(4 sides)
These are regular polygons
4
4
4 5
5
5
5 2
2
2
2
2
2
2
2
3
3
3
3
3
Classifying Angles(Review)
Acute AngleAn acute angle has a measure between 0° and 90°.(a cute = little)
Right Angle
A right angle has a measure of 90°.(square = right = 90°)
Obtuse AngleAn obtuse angle has a measure between 90° and 180°.(obtuse = obese)
Straight AngleA straight angle has a measure of 180°.(straight = flat)
Classifying Triangles(Review)
Classifying Triangles
•Equilateral triangle• All sides are the same (equal) length.
The sum total of every triangle = 180°So, if all of the angles are the same…3 ÷ 180° = 60°Each of the three angles of an equilateral triangle is 60°
Classifying Triangles
•Isosceles triangle• At least two sides are the same (equal)
length.
6
4
4 4
4
Classifying Triangles
•Scalene triangle• No sides are the same (equal) length.
9
7
2
9
72
Classifying Triangles
•Right triangle• One angle is a right (90°) angle.
• The sides have special names.• The legs are the two sides that form a right triangle• The third side is the hypotenuse
legs legs
hypotenuse hypotenuse
Classifying Triangles
•Acute triangle• All three angles are acute angles.
Classifying Triangles
•Obtuse triangle• One angle is an obtuse angle.
Classifying Quadrilaterals
Classifying Quadrilaterals
• How do you classify quadrilaterals?• Quadrilaterals can be classified by their
• angles • pairs of sides.
• Remember that a quadrilateral is any polygon with 4 sides.
Classifying Quadrilaterals
• Types of quadrilaterals?
Parallelogram Rectangle Rhombus Square Trapezoid
Classifying Quadrilaterals
•Parallelogram• A quadrilateral with both pairs of opposite
sides • parallel• equal in length.
Parallelogram
Rectangle Rhombus
Square
Classifying Quadrilaterals
•Rectangle• A parallelogram with four right (90°)
angles.
RectangleRectangles
& rhombuses are special parallelograms.
Square
Classifying Quadrilaterals
•Rhombus• A parallelogram with all sides the same
length. Rhombus
Rectangles & rhombuses are special parallelograms.
Square
Classifying Quadrilaterals
•Square• A rectangle with all sides the same length.
SquareA square is a special rectangle. It is also a special rhombus.
Classifying Quadrilaterals
•Trapezoid• A quadrilateral with only one pair of
parallel sides.
Trapezoid
A
D
C
B
side A ll side C
side B ll side D
Quadrilateral Videos
ixl Classify Quadrilaterals
You now know all about Plane Figures!