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Reteaching 7-1. Sample answers: XZ, WZ, WX, XY, YZ, ZM, or MX M, W, X, Y or Z WX and XY, WZ and ZY WZ and XY A. parallel 5b. Intersecting A B BC. Reteaching 7-2. 146°; obtuse 34°; acute 50°; acute 90°; right. Reteaching 7-3. Scalene; obtuse Equilateral; acute - PowerPoint PPT Presentation
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RETEACHING 7-11.Sample answers: XZ, WZ, WX, XY, YZ, ZM, or MX
2.M, W, X, Y or Z
3.WX and XY, WZ and ZY
4.WZ and XY
5.A. parallel 5b. Intersecting
6. A B
7.B C
RETEACHING 7-2
1.146°; obtuse
2.34°; acute
3.50°; acute
4.90°; right
RETEACHING 7-3
1.Scalene; obtuse
2.Equilateral; acute
3.Isosceles; right
4.Scalene; obtuse
5.scalene; acute
6.Isosceles; acute
7.X=105°
8.X=34°
What is a Polygon????
Any ideas?Write down what you think it is for #1.
POLYGONSExploring
WHAT IS A POLYGON?
Polygons are many-sided figures, with sides that are line segments. Polygons are named according to the number of sides and angles they have. Can be “regular” – all sides and all angles are equal to each other
ISOSCELES TRIANGLES
Two sides of equal lengthThree acute anglesSum of angles = 180°
Hint: Think “Tri”cycle, “tri”pod, “Tri”lateration (Tri means 3)
EQUILATERAL TRIANGLES
All sides equal lengthThree acute angles Sum of angles = 180°Is a regular polygon
SCALENE TRIANGLES
No sides are equalNo angles are equalMay have obtuse angleSum of angles = 180 °
Classifying Polygons by # of Sides
4 sided Polygon = Quadrilateral
Hint: Think “Quad”rant, “Quad”ruple, “Quad” (AKA 4-Wheeler)
RECTANGLES
Opposite sides are parallelOpposite side are equal in lengthEach angle equals 90°Sum of angles = 360°
SQUARES
All sides equalAll angles equal and are 90 ° eachSum of angles = 360 °Is a regular polygon
TRAPEZOIDS
Two sides are parallelHas obtuse and acute anglesSometimes has a right angleSum of angles = 360 °
RHOMBUSES (RHOMBI)
All four sides of equal lengthOpposite angles are equal – 2 acute angles, 2 obtuse anglesSum of angles = 360 °Regular polygon
PARALLELOGRAMS
Opposite sides parallelOpposite sides equal in lengthOpposite angles equalSum of angles = 360 °
PENTAGONS
5 sides Sum of
angles = 540 °
Regular polygon
Hint: Think “Pent”athalon, or the government building “The Pentagon”
HEXAGONS
6 sides Sum of angles =
720 ° Can be regular
polygon
Hint: Both “Hexagon” and “Six” have an ‘x’ in them
OCTAGONS
8 sides Sum of angles =
1080 ° Can be regular
polygon
Hint: “oct”opus – 8 legs
DECAGONS
10 sides Sum of angles =
1440° Can be regular
polygon
Sum of angles in a REGULAR POLYGON:
(n-2)180
Remember n=number of sides
Each interior angle in a regular polygon:
(n-2)180/n
REGU LAR PO LYGO N: INTERIO R ANG LE SU M
REGULAR HEXAGON
INT ANGLE SUM =(6 – 2 ) 180 = 720°
EACH INT ANGLE = 720 = 120°
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