Angles

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Angles
Types of Angles
Naming Angles
Measuring Angles
Drawing Angles
Calculating Missing angles
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Vertically Opposite Angles
Compass Points
Three Figure Bearings
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Starter Questions
Q1. Convert to the 24 hour clock.
(b) 650 am
(a) 725 pm
Q2. Is an obtuse angle less than 90 deg.
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Q3. Does 234 47 2 313 Explain your answer?
Q4. Round the following to nearest hundred.
(a) 501
(b) 9 765
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Type of Angles
Learning Intention
Success Criteria

• To be able to identify acute, right-angle,
  obtuse, straight line
• and reflex angles.

1. Explain some types of Angles at level D.

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Type of Angles
Acute less than 90o
Obtuse Between 90o 180o
Right - Angle exactly 90o
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Straight Line Angle exactly 180o
reflex over 180o less than 360o
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Type of Angles
Now try Ch8 (page 87) Exercise 1
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Starter Questions
Q1. Convert to the 12 hour clock.
(b) 0540
(a) 1715
Q2. Write down 2 numbers that add to give 8
and multiply to give 15.
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Q3. Does 565 73 482 Explain your answer
Q4. Round the following to nearest 100.
(a) 13,551
(b) 369,449
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Naming Angles
Learning Intention
Success Criteria

1. To be able to name an angle.

1. To explain how we name angles by THREE capital
   letters with the angle sign. The middle letter
   being where the angle is.

1. Understand the difference between the type of
   angle and the name of an angle.

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Naming Angles
A
D
B
C
Type of angle is right angle
Type of angle is obtuse
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Name of angle is ? ABC
Name of angle is ? ZYX
Type of angle is acute
Name of angle is ? CBD
MIDDLE LETTER IS ALWAYS WHERE THE ANGLE IS
ALWAYS 3 CAPITAL LETTERS
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Naming Angles
Now try Ch8 (page 88) Exercise 2
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Starter Questions
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Measuring Angles
Learning Intention
Success Criteria

1. To be able to measure angle using a protractor.

1. To show how to measure angles of various type.

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A 180o Protractor
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1. Look directly down onto the cross point.
2. Always use the protractor in a horizontal
manner as shown below.
?
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Measuring Angles with a 180o Protractor
50o
67o
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Measuring Angles with a 180o Protractor
120o
135o
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Measuring Angles
Now try Ch8 (page 90) Exercise 3
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Starter Questions
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Drawing Angles
Learning Intention
Success Criteria

1. To be able to draw an angle using a ruler and
   protractor.

1. To show how to daarw angles of various type.

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Drawing Angles
Example Draw an angle BAC of 300
Step 1 Draw line AC6cm
Step 2 Measure an angle of 30o and put an X
beside it.
B
X
Step 3 Draw the line through X. Label it B.
30o
A
C
Step 4 Put in the angle value and name the angle.
? BAC 30o
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Drawing Angles
Example Draw an angle STU of 1100
S
Step 1 Draw line TU6cm
X
Step 2 Measure an angle of 110o and put an X
beside it.
Step 3 Draw the line through X. Label it S.
110o
T
U
Step 4 Put in the angle value and name the angle.
? STU 110o
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Drawing Triangles
R
40o
Q
30o
P
Example Draw to scale the triangle PQR with
PQ 8cm and angle RPQ 30o and RQP 40o
Step 1 Draw line PQ 8cm
Step 2 Measure Angle RPQ from P 30o
R
Step 3 Measure angle RQP from Q 40o
Q
P
Step 4 Where lines cross is point R
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Drawing Angles
Now try Ch8 (page 92) Exercise 4
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Starter Questions
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Find Missing Angles
Learning Intention
Success Criteria

1. To know 360o in a circle.

1. To calculate missing angle give all other angles.

1. Find the missing angle in a right angle, straight
   line and vertical opposite angle.

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Find Missing Angle
55o
115o
Two angles making a straight line add to
180o (Supplementary angles)
Two angles making a right angle add to
90o (Complementary angles)
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145o
Angles round a point always add up to 360o
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Find Missing Angle
Now try Ch8 (page 93) Exercise 5
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Starter Questions
Q1. Find the value of x
Q2. Find two numbers that multiply to give 6 and
add to give 5.
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Q3. Does 240 10 24 Explain your answer.
Q4. I divide a cake in 6 pieces and eat 1 of
them. What fraction have I eaten.
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Vertically Opposite Angles
Vertically Opposite
Learning Intention
Success Criteria

1. To understand the term vertically opposite.

1. To explain the property of vertically
opposite angles.
2. To be able to use property to solve problems.
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Vertically Opposite Angles
146o
146o
angles opposite each other at a cross are equal.
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131o
49o
38o
110o
49o
131o
142o
142o
70o
70o
38o
110o
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Vertically Opposite Angles
Now try Exercise 6 Ch8 (page 95)
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Starter Questions
Q1. Does 182 75 103 Explain.
Q2. Find two numbers that multiply to give
48 and divide to give 3.
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Q3. Find the missing angles
119o
co
ao
bo
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Compass Points
Learning Intention
Success Criteria

1. To understand the directions on a compass.

1. To explain the basic points on a compass in
terms of direction and degrees.
2. To be able to use compass points and degrees
to solve problems.
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Compass Points
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If Lewis walks to Jamie then to Ryan and then
back to where he started. Write down all the
directions he took.
If Laura walks to Julie then to Danielle and then
back to where she started. Write down all the
directions she took.
If Daniel is facing North and turns clockwise to
face Laura. How many degrees is this.
If Daniel is facing Frances and turns clockwise
to face Danielle. How many degrees is this.
If Danielle is facing Paul and turns
anti-clockwise to face Daniel. How many degrees
is this.
Who is North of Daniel
Who is East of Jamie
Who is South West of Ryan
Who is North East of Lewis
Compass Points






Frances
Jamie
Ryan
N
Daniel
Julie
Laura
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Danielle
Lewis
Paul
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Compass Points
Now try Exercise 8 Ch8 (page 98)
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Starter Questions
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Bearings
Learning Intention
Success Criteria
1. Understand what bearing is.
1. To explain what a bearing is and how to
measure and draw a bearing.
2. Measure and draw a bearing.
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1. Measured from North.
060o
2. In a clockwise direction.
3. Written as 3 figures.
315o
230o
145o
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Bearings
Use your protractor to measure the bearing of
each point from the centre of the circle.
(Worksheet 1)
A 360o protractor is used to measure bearings.
Worksheet 1
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Estimate the bearing of each aircraft from the
centre of the radar screen.
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Drawing a Bearings
Draw a bearing of (a) 50o (b) 230o
N
N
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50o
230o
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Compass Points
Worksheet 1
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My Estimated Bearing True Bearing Error
1
2
3
4
5
6
7
8
9
10
11
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Total Error
Average Error
My Estimated Bearing True Bearing Error
1
2
3
4
5
6
7
8
9
10
11
12
Total Error
Average Error
Worksheet 2 (Radar)
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Bearings
Now try Ex 9 Ch8 (page 100)
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