Related angles

Related Angles

1. Block 3
Related Angles

2. Finding all the relations
There are 4 related angles (usually)
Less than 90
0
Between 90
0
and 180
0
Between 180
0
and 270
0
Between 270
0
and 360
0
a
0
a
0
180 – a
180 + a
360 – a
320
0
140
0
220
0
40
0

3. Finding relations using NWD
a
0
180 – a
180 + a360 – a
iii
iii iv
Easiest when starting
in Quadrant 1
(Acute angle)
Relations of 70
0i 70
0
ii 180 – 70 = 110
0
iii 180 + 70 = 250
0
iv 360 – 70 = 290
0
AS
T C

4. Relations from non acute angles
Ex230
0
180 – a
180 + a
iii
iii iv
a
0
360 - a
AS
T C
Quad iii
so 180 + a = 230
0
a = 50
0
can easily find
rest of relations
180 – 50 = 130
0
360 – 50 = 310
0
0
0
90
0
180
0
270
0

5. Relations from non acute angles
Ex330
0
180 – a
180 + a
iii
iii iv
a
0
360 – a
AS
T C
Quad iv
so 360 – a = 330
0
a = 30
0
rest of relations
180 – 30 = 150
0
180 + 30 = 210
0
0
0
90
0
180
0
270
0

6. Relations from non acute angles
Ex330
0
180 – a
180 + a
iii
iii iv
a
0
360 – a
AS
T C
Quad iv
so 360 – a = 330
0
a = 30
0
rest of relations
180 – 30 = 150
0
180 + 30 = 210
0
0
0
90
0
180
0
270
0