Exterior Angles of Regular Polygon

Exterior Angles of Regular Polygon

​Sum of Exterior Angle = 360^o

​Remember this:

​Any polygons will have the same value of sum of exterior angles

​What is Exterior angle?

​Triangle

Sum of exterior angle =

An exterior angle =

​Pentagon

Sum of exterior angle =

An exterior angle =

​Example 1

​Find b

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​

​Example 2

​Find the exterior angle of a regular Decagon

​

​Answer:

​

​Decagon have 10 sides

​n = 10

​

​An exterior angle

​QUIZ

​Get ready with your calculator

Fill in the Blanks

Find a 

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Find b

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Find c

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Find d

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Find a

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Find a

Fill in the Blanks

Find b

Fill in the Blanks

What is the size of an exterior angle on a regular 18 sided shape?

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What is the size of an exterior angle on a regular 9 sided shape?

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 A regular polygon has exterior angles of size 18⁰, how many sides does it have?

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A regular polygon has exterior angles of size 4⁰, how many sides does it have?

​Interior angle + Exterior angle = 180^o

​Example 3

​  A regular polygon has an interior angle of 171⁰. What is the exterior angle and hence, how many sides does the polygon have?

​

​Answer:

​

​Exterior angle = 180^o - 171^o = 9^o

​

​Number of sides=

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 A regular polygon has an interior angle of 157.5⁰. What is the exterior angle and hence, how many sides does the polygon have?

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 A regular polygon has an interior angle of 120⁰. What is the exterior angle and hence, how many sides does the polygon have?

​What have you learn today?

​and........