Angles — South Australian Year 3 Maths
What an angle is, naming the vertex and arms, finding angles in shapes and everyday objects, then comparing angles with a right angle. Two subtopics and 40 practice questions, aligned to AC9M3M05.
Angles in South Australian Year 3
An angle shows how far two arms open from the point where they meet, the vertex. In this topic students find angles in shapes and in things around them, compare how wide angles open, and use the right angle, a square corner, to judge whether other angles are smaller, equal or larger.
The two subtopics below are Identify angles in shapes and the environment and Compare angles to a right angle. Angles is one of the 18 topics in South Australian Year 3 Maths and belongs to the Measurement strand. Both subtopics come under Australian Curriculum code AC9M3M05. These skills lead on to naming and measuring angles in later years.
Subtopics
Angles: common questions
How do you explain an angle to a child?
Open a pair of scissors or a book a little, then wider. The point where the two parts join is the vertex and the two parts are the arms. The wider they open, the bigger the angle; making the arms longer does not change it.
What is a right angle?
A right angle is a square corner, like the corner of a sheet of paper, and it is a quarter turn. Use the paper corner as a tester: if an angle fits exactly it is a right angle, if it is narrower it is less, and if it opens past the paper it is greater.
How many angles does a shape have?
Every corner is an angle, so count the corners. A shape with 7 straight sides has 7 corners, so it has 7 angles. Children sometimes miss a corner or count one twice; marking each corner with a dot as you count helps.
How can we practise angles at home?
Go on an angle hunt. Look for right angles in windows, doors and books, and for angles smaller or larger than a right angle in clock hands, open laptops and coat hangers. Ask which of two angles opens more, and why.
Which curriculum codes cover Angles in South Australian Year 3?
Both subtopics come under Australian Curriculum v9 code AC9M3M05, which treats an angle as an amount of turn and uses the right angle as the yardstick for comparing angles found in daily life.