Angle RulesWALT: familiarise ourselves

with angle rules and use them to solve problems.

S1: Answer in your books:

What are parallel lines? (Draw a diagram).

What are perpendicular lines? (Draw a diagram).

10/10/12

Facts:

There are three types of angles...

Lets have a quick practise...

ObtuseAcute

Reflex

Rule 1:

Angles on a straight line add up to...

180 degrees.

Rule 2:

Angles around a point add up to....

360 degrees.

Rule 3:

Angles in a triangle add up to...

180 degrees.

Rule 4:

Angles in a quadrilateral add up to...

180 degrees.

M1Task:

Complete the true/false task in front of you.

Organise them on a spare part of your desk, when you are

confident and have discussed with your partner, stick them into your books in table form.

A reflex angle is between 90˚ and 180˚

An acute angle is less than 90˚

The interior angles of a triangle add up to 180˚

Angles around a point add up to 180˚

There are 180˚ in a straight line

An isosceles triangle has 3 equal sides and 3

equal angles.

Each angle in an equilateral triangle

measures 60˚

Intersecting lines are lines that never cross

each other.

Parallel lines are lines that cross each other.

If you know all the angles that are in a

triangle, you can draw the exact triangle.

Parallel lines are marked with arrows.

Equal lines are marked with dashes.

Quadrilaterals have 4 sides.

The interior angles of a quadrilateral add up to

180˚

A square is a regular quadrilateral.

An obtuse angle is between 90˚ and 180˚

Right-angled triangles have two sides that are

the same length.

Triangles have at least one angle that is a reflex

angle.

True False Angles around a point add up to 360˚

P1Reflect:

What facts did you get wrong and what can you do to help you remember

them from now on?

M2Task 2:

Find the missing angles using the rules.

15o

27o

a

P2Reflect:

Are you able to use angle rules to find missing

angles?