Download presentation
Presentation is loading. Please wait.
1
ANGLES ON A STRAIGHT LINE ADD UP TO 180°
25/02/2019 ANGLES ON A STRAIGHT LINE ADD UP TO 180°
2
Angles on a straight line add up to 180
25/02/2019 Angles on a straight line add up to 180 a b a + b = 180° because there are 180° in a half turn.
3
25/02/2019 Examples x b 70o 35o Angle x = 180 – 35 = 145o
Angle b = 180 – 70 = 110o Angle x = 180 – 35 = 145o
4
Task Find the size of the missing angles
25/02/2019 Task Find the size of the missing angles x 47o 1 114o y 2 3 4 76o a 82o b Angle x = 180 – 47 = 133o Angle y = 180 – 114 = 66o Angle a = 180 – 76 = 104o Angle b = 180 – 82 = 98o
5
25/02/2019 43° 65° 44° 122° 60° 93° 90° 110° 30° 66°
6
VERTICALLY OPPOSITE ANGLES ARE EQUAL
25/02/2019 VERTICALLY OPPOSITE ANGLES ARE EQUAL
7
25/02/2019 When two lines intersect, two pairs of vertically opposite angles are formed. a d b c a = c and b = d Vertically opposite angles are equal
8
25/02/2019 b 35 a Find the size of the angles a and b giving a reason
9
ANGLES AT A POINT ADD UP TO 360°
25/02/2019 ANGLES AT A POINT ADD UP TO 360°
10
Angles around a point add up to 360
25/02/2019 Angles around a point add up to 360 b a c d a + b + c + d = 360 because there are 360 in a full turn.
11
25/02/2019 Example a 75o 85o 80o + Angle a = 360 - (85 + 75 + 80)
240 Angle a = ( ) = = 120o
12
25/02/2019 Examples You might also need to use other angle rules and knowledge to help you solve problems involving angles at a point 167° a 69° 68° d 103° 43° c 43° b 137°
13
ANGLES IN A TRIANGLE ADD UP TO 180°
25/02/2019 ANGLES IN A TRIANGLE ADD UP TO 180°
14
The angles in a triangle add up to 180°
25/02/2019 a b c For any triangle, a + b + c = 180° The angles in a triangle add up to 180°
15
25/02/2019 Examples 65o Calculate angle a a 27o Calculate angle a a
16
Calculate angles a, b and c
25/02/2019 Examples Calculate angles a, b and c a b c Since the triangle is equilateral, angles a, b and c are all 60o (180÷3)
17
25/02/2019 90° 60° 70° 26° 55° 90°
18
ANGLES IN A QUADRILATERAL ADD UP TO 360°
25/02/2019 ANGLES IN A QUADRILATERAL ADD UP TO 360°
19
The angles in a quadrilateral add up to 360°
25/02/2019 d c a b For any quadrilateral, a + b + c + d = 360° The angles in a quadrilateral add up to 360°
20
25/02/2019 Angles TASK 1 EXTENSION 1)
Calculate the value of the missing angles below: j 150º 80º 30º EXTENSION 1) Calculate the value of x below:
21
25/02/2019 Solutions EXTENSION 1) Calculate the value of x below:
j 100º 150º 80º 30º EXTENSION 1) Calculate the value of x below: 3x + 10 + 2x – 4 + x + 8 + 28 = 360 6x + 42 = 360 6x = 318 x = 53
22
Find the missing angles, giving reasons for your answers
25/02/2019 Find the missing angles, giving reasons for your answers 1) 2) 97° 75° 130° k i j 85° 90° 52°
23
25/02/2019 Solutions 2) 1) 97° 121° k 75° 130° 52° j 90° i 70° 85° 52°
Vertically opposite angles are equal Angles in a quadrilateral add to 360° Angles in a quadrilateral add to 360°
24
BASE ANGLES IN AN ISOSCELES TRIANGLE ARE EQUAL
25/02/2019 BASE ANGLES IN AN ISOSCELES TRIANGLE ARE EQUAL
25
Base angles in an isosceles triangle are equal
25/02/2019 Base angles in an isosceles triangle are equal
26
Calculate angles x and y
25/02/2019 Example a 65o Calculate angle a b Angle a = 65o (base angles of an isosceles triangle are equal). Angle b = 180 –( ) = 180 – 130 = 50o Calculate angles x and y y 130o x
27
25/02/2019 650 1) 2) 3) 4) 500 600 500 x 500 800 x x 400 x 200 400 5) 6) 7) 300 8) 450 x 700 700 x x x 600 11) 10) 9) x 12) 600 400 200 350 72.50 x 800 400 300 x x
28
ALTERNATE ANGLES ARE EQUAL, AND CORRESPONDING ANGLES ARE EQUAL
25/02/2019 ALTERNATE ANGLES ARE EQUAL, AND CORRESPONDING ANGLES ARE EQUAL
29
25/02/2019 Corresponding angles are equal Alternate angles are equal
Interior angles add up to 180° a a a b b b a = b a = b a + b = 180° Look for an F-shape Look for a Z-shape Look for a C- or U-shape
30
25/02/2019
31
25/02/2019
32
25/02/2019
33
25/02/2019
34
25/02/2019
35
25/02/2019
36
25/02/2019
37
25/02/2019
38
25/02/2019
39
25/02/2019 x 100o y z 60o
40
25/02/2019 105o z 55o x y
41
25/02/2019 58o a b e c g f d 70o h
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.