In this activity, we will be looking at angle problems involving all the rules we have learnt previously!

Let's recap what we know already!

Make a note of what you need here!

*Angles around a point = 360 ^{o}*

*Angles in a straight line = 180 ^{o}*

*Angles in triangles = 180 ^{o}*

*Angles in polygons = 180 x (number of sides - 2)*

*Vertically opposite (X) angles are equal*

*In parallel lines - (Z) alternate angles are equal*

*In parallel lines - (F) corresponding angles are equal*

*In parallel lines - (C) co-interior angles add up to 180 ^{o}*

*Polygons - exterior angle = 360 ÷ number of sides*

*Polygons - interior angle = 180 - exterior angle*

Typical geometry questions will have a mixture of these rules included!

Let's have a look at a typical question.

__Example__

Calculate the missing angle A.

**Answer**

**Step 1** - Angles in a straight line with 126^{o}

180 - 126 = **54 ^{o}**

**Step 2** - The triangle is** isosceles so both the base angles are the same**

**Step 3** - Angles in a triangle add up to 180^{o}

We now have two angles so we can find the third one

A = 180 - (54 + 54)

A = 180 - 108

**A = 72 ^{o}**

Let's have a go at some other questions now.