MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Revision of Level E

Interior / Exterior Angles

Angle PropertiesAngle Propertiesw

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Angles in Time

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Starter Starter QuestionsQuestions

1. Calculate the volume of the following shapes.

Q2. Find 3.5% of £ 200.

Q.3 Calculate

(a) - 6 - (7 - 8) (b) (-10) x (-3) (c) (-2) x (-12) 4

5 cm

3 cm

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10 cm

3 cm

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Learning IntentionLearning Intention Success CriteriaSuccess Criteria

1.1. Remember basic Remember basic properties for angles.properties for angles.

1. We are reviewing angle properties.

2.2. Apply properties to Apply properties to solve angle problems..solve angle problems..

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Angle PropertiesAngle PropertiesRevision of Level E

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

120o 95

o

Angle Angle PropertiesProperties

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Angles round a pointAdd up to 360

o

115o

Two angles making astraight line add to 180

o

angles opposite each otherat a cross are equal.

34o 34

o

3 angles in a triangle ALWAYSadd up to 180

o.

50o

40o

65o

90o146o

146o

145o

Revision of Level EMTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Angle Angle PropertiesProperties

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Two angles in a isoscelesAre equal

ALL angles in an equilateral triangle are 60

o

d = 115oa

o

co

bo

go

fo

ho

eo

is corresponding to d and must be 115

o

is opposite to d and must be 115o

is must be 65o (straight line)

is alternate to c and must also be 65o

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Revision of Level EMTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Now try Exercise 1Ch3 (page 21)

Copy out shapes

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Angle Angle PropertiesProperties

Revision of Level E

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Starter Starter QuestionsQuestions

Q2. Find 5.5% of £ 300.

Q.3 Calculate

(a) - 4 - (17 - 6) (b) (-8) x (-8) (c) (-3) x (-20) 4

1. Calculate the volume of the following shapes.

7 cm

5 cm

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20 cm

3 cm

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Learning IntentionLearning Intention Success CriteriaSuccess Criteria

1.1. To know the term To know the term polygon.polygon.

1. We are exploring interior and exterior angles of a polygon .

2.2. Understand steps for Understand steps for calculating the interior calculating the interior and exterior angle of a and exterior angle of a polygon.polygon.

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PolygonsPolygonsInterior and Exterior Angles

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Laffertyww

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PolygonsPolygons

A polygon is a “many-sided closed straight-lined figure”

This 5-sided (polygon) is called a PENTAGON

Irregular Pentagon

Interior and Exterior Angles

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Laffertyww

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PolygonsPolygons

A polygon is a “many-sided closed straight-lined figure”

Pentagon Hexagon Octagon

If all the sides and angles are the same it is calledREGULAR POLYGON. We will only be dealing withregular polygons in this section.

Interior and Exterior Angles

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Laffertyww

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PolygonsPolygons

Some useful points about regular polygons :• All the triangles around the centre are isosceles.

Pentagon

72o

Hexagon

60o

Octagon

45o

Interior AnglesInterior Angle

• Angle at the centre is 360o• To find one angle at the centre, take 360o and

divide it by how many triangles you have

Interior and Exterior Angles

18 Apr 2023 Created by Mr. Lafferty

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Level F - Polygons Worksheet Ex2

Decagon (10 sided)

Heptagon (7 sided)Hexagon (6 sided)Pentagon (5 sided)

Octagon (8 sided) Nonagon (9 sided)

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Now try Exercise 2Ch3 (page 23) Q1-Q6Use worksheet Provide

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PolygonsPolygonsInterior and Exterior Angles

MTH 3-17a

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Laffertyww

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PolygonsPolygons

What you should have found :Polygon sides 4 5 6 7 8 9 10 11 12

Sum of Angles 360 540 720 900 1080 1260 1440 1620 1800

Size of I nterior Angle 90 108 120 129 135 140 144 149 150

Interior angle = 180 – (360÷n)

n = Number of sides

eg . A hexagonal has interior angle is:

Interior angle = 180 – (360÷6) = 120o

Interior and Exterior Angles

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Laffertyww

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PolygonsPolygons

eg . For the pentagon above :

Exterior angle = 180 – interior angle

Pentagon

This is called the“Exterior angle”

B

A

E

CD

O

Q

Exterior angle = 180 – 108 = 72o

Interior and Exterior Angles

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Now try Exercise 2Ch3 (page 23) Q8-Q9Use worksheet Provide

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PolygonsPolygonsInterior and Exterior Angles

MTH 3-17a

MTH 3-17a

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Starter Starter QuestionsQuestions

Q2. Find 7.5% of £ 600.

Q.3 Calculate

(a) - 6 +(23- 5) (b) (-15) x (-10) (c) (-32) x (-4) 4

1. Calculate the volume of the following shapes.

10 cm

3 cm

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7 cm

4 cm

18 Apr 202318 Apr 2023 Created by Mr. LaffertyCreated by Mr. Lafferty

Practice on AnglesNow try Exercise 3

Ch3 (page 26)

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PolygonsPolygonsInterior and Exterior Angles

MTH 3-17a