1. Which ones are you using?
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Which ones are you using?
PLT Skills
LESSON OBJECTIVES
We are learning to:
Enhance Mathematical basic skills knowledge. (Which PLT skills?)
Accurately calculate missing angles involving algebra. (Grades D-C)
Always aim high!
Where are we in our journey?
Real life cross/curricular links?
AUTHOR

2. Which ones are you using?
Creative Thinker
LEARNING JOURNEY
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Independent Enquirer
Reflective Learner
Self Manager
Team Worker
PLT Skills
Which ones are you using? 2

3. Which ones are you using?
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STARTER
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PLT Skills
Which ones are you using?
TASK
Calculate the value of the missing angles below: d 1) 2)
136º 3)
80º 4) b
54º
115º a
30º c
65º
20º
72º
54º
136º
140º 5) 6) 7)
50º j
135º
160º i
60º
65º
65º e f g
60º
60º
45º h
20º 3

4. Which ones are you using?
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PLT Skills
ANGLES AND ALGERBA
Which ones are you using?
EXAMPLES
1) Work out the values of x below:
(c)
(a)
(b) x
2x - 3 4x x
3x + 20 3x 45
3x - 5
2x - 3 + x
= 90
3x + 20 + x
= 180
3x - 5 + 4x + 45 + 3x
= 360 3x
- 3 = 90 4x
+ 20 =
180
10x
+ 40 =
360
+ 3
+ 3
- 20
- 20
- 40
- 40 3x = 93 4x =
160
10x =
320
÷ 3
÷ 3
÷ 4
÷ 4
÷ 10
÷ 10 x =
31° x =
40° x =
32° 4

5. Which ones are you using?
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PLT Skills
ANGLES AND ALGERBA
Which ones are you using?
TASK (GRADE D) 1)
Work out the value of the missing angles below:
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h) 5

6. Which ones are you using?
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ANGLES AND ALGERBA
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EXTENSION 1 (GRADE D) 1)
Work out the value of the missing angles below:
(b)
(c)
(a)
70°
(d)
(e)
(f) 6

7. Which ones are you using?
Creative Thinker
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ANGLES AND ALGERBA
Which ones are you using?
EXTENSION 2 (GRADE C) 1)
Work out the value of the missing angles below:
(a)
(b)
(c)
108°
108°
108°
51°
108°
108° 5x
= 60
÷ 5
÷ 5 x =
12° 7

8. Which ones are you using?
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PLT Skills
ANGLES AND ALGERBA
MINI-PLENARY ACTIVITY
Work out the value of each angle in the quadrilateral below:
36°
144°
108°
72° 4y + 3y + 2y + y =
360
10y =
360
÷ 10
÷ 10 y =
36° 8

9. Which ones are you using?
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DISCOVERY
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PLT Skills
Which ones are you using?
LINK BACK TO OBJECTIVES
Accurately calculate missing angles involving algebra.
What grade are we working at? 9

10. Which ones are you using?
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PLT Skills
ANGLES AND ALGERBA
PLENARY ACTIVITY – EXAM QUESTION (GRADE D)
In the diagram AB is parallel to CD.
105°
25°
Not drawn
accurately
50°
(a)
Work out the value of x.
(b)
Work out the value of y.
Give a reason for your answer. 2x
+ x
+ 105 =
180
y =
180° - 105° - 25° 3x
+ 105 =
180 y =
50°
- 105
- 105 3x = 75
Alternate angles are equal
Angles in a triangle add up to 180°
÷ 3
÷ 3 x =
25°
(2 marks)
(2 marks) 10

11. Where are we in our journey? What grade we working at?
What have you learnt?
Draw your brain
In your brain, write or draw everything you can remember about accurately calculating angles involving algebra. It can be a skill or a reflection, or something else that might be prominent in your brain.
Where are we in our journey?
What grade we working at?

12. Which ones are you using?
Creative Thinker
Effective Participator
Independent Enquirer
Reflective Learner
Self Manager
Team Worker
Which ones are you using?
PLT Skills
How well do you understand the task? .
I don’t understand
I nearly understand
I fully understand

13. Think about how you can improve your work.
Plenary Activity
WWW (What Went Well)
EBI (Even Better If)
On your post it notes…
Think about how you can improve your work.