1. Angles : All you should know
By the end of the lesson you will be able to :
• Use appropriate mathematical vocabulary
related to angles.
• Recognise and calculate angles between parallel
lines.
• Use angle properties of triangles and quadrilaterals.
1

2. What do you call an angle whose measure
is less than 90o? Acute
is 135o? Obtuse 360º?
A complete turn
is180º? Straight angle
Which of the following angles is a reflex angle?
a) 178º b) 200º c) 270º d) 320º e) 360º
b) c) and d)
reflex angle :
2

3.
What is the complementary angle of α= 26o ?
An angle of 64o.
complementary angles:
supplementary angles:
3

4. What is the name for angles 1 and 2?
Vertically opposite. 1
2
Vertically opposite angles are equal.
4

5. Two vertically opposite angles measure 2x and 80o.
How many degrees are there in x? o
40
1
2x 80º
2
Two supplementary angles measure (5x­30) and
(x+90) degrees. What is the value of x ?
20o
5

6. Classify the angles below according to their
position.
α and β are adjacent
α
β
What can be said about the
values of angles α and β?
α + β = 180o
Adjacent angles add up to 180o.
6

7. a // b c
a 1 2
4 3
b 5 6
8 7
Name all interior angles.
3,4, 5 and 6
Name all exterior angles.
1, 2, 7, 8.
7

8. a // b c
a 1 2
4 3
b 5 6
8 7
Name all pairs of alternate interior angles.
4 and 6, 5 and 3
Name all pairs of alternate exterior angles.
1 and 7, 2 and 8.
Alternate angles between parallel lines are.............
8

9. a // b c
a 1 2
4 3
b 5 6
8 7
Name all pairs of corresponding angles.
1and 5, 2 and 6, 4 and 8, 3 and 7.
Corresponding angles between parallel lines are .............
9

10. a // b c
a 1 2
4 3
b 5 6
8 7
Name all pairs of cointerior (or conjugate interior)
angles. 5 and 4, 3 and 6
Name all pairs of coexterior (or conjugate exterior)
angles.
1 and 8, 2 and 7.
Conjugate angles between parallel lines......................
10

11. a Which line is the transversal?
p
r
1 140o
p // a Find the measure of:
2
3 140o
o
r 140
40o
11

12. a // b What is the value of x ?
(x+80)o
20
a
b (5x)o
c
12

13. Find the size of
o
18
13

14. Triangles clasification by sides
...................... ...................... ......................
14

15. by angles
....................
....................
....................
15

16. B
o
Find the size of
2x+ 10
60o
3x + 40o C
x ­ 20o
A
The sum of the interior angles of any triangle
is........
16

17. B
48o
α+θ=
θα
o T α =
52
P
α is an exterior angle, because is adjacent to an
interior angle of the triangle PBT.
17

18. Quadrilaterals
Quad Family Tree.notebook
18

19. G H What is the name of this shape?
>
o
Trapezium
72o 49
J > I
What is the value of ? 108o
What is the value of ? 131o
The sum of all the interior angles of a quadrilateral
is...............
19

20. Solve from book in page 115: Ex 1
20

21. Attachments
Quad Family Tree.notebook