Answer:
a) a= 60
c) a= 135
d) a= 40
f) a= 115
g) a= 37
i) a= 130
Step-by-step explanation:
If you see a little square at the angle, this means that the angle is a right angle, which means that it is 90°.
Let's look at Q5a.
a) a° +30°= 90°
a°= 90° -30°
a°= 60°
a=60
Questions 5b has the same concept.
The sum of the angles on a straight line is 180°. The abbreviation used for this is (adj. ∠s on a str. line).
Let's look at Q5c.
c) a° +45°= 180° (adj. ∠s on a str. line)
a°= 180° -45°
a°= 135°
a= 135
Question 5d uses the same concept too.
Let's look at Q5d.
d) 90° +50° +a°= 180° (adj. ∠s on a str. line)
a°= 180° -90° -50°
a°= 40°
a= 40
Vertically opposite angles are equal. The abbreviation written for this is (vert. opp. ∠s).
Use this for questions 5f and 5g.
f) a°= 115° (vert. opp. ∠s)
a= 115
g) a°= 37°
a= 37
The sum of angles on a point is 360°. This will help you solve questions 5h and 5i.
i) 140° +90° +a° = 360° (∠s at a point)
a° +230°= 360°
a°= 360° -230°
a°= 130°
a= 130
