Shapes are named by how many sides they have
Three sides is a triangle, four is a quadrilateral, five a pentagon, six a hexagon. Stretching or turning a shape does not change its name.
Class 3 to 10 · 95 games
Shapes and angles, explained with pictures
Sorting shapes by their sides, and measuring the turn at a corner.
In everyday life: Floor tiles, a rangoli pattern, the corner of a page, the hands of a clock.
An angle measures a turn, not a length
A square corner is a right angle, 90 degrees. Less than that is acute, more is obtuse. Long arms drawn on a small angle do not make the angle bigger.
The three angles of any triangle add to 180 degrees
Any triangle at all — thin, wide, tilted. So if you know two angles, the third one is already decided.
A worked example
A triangle has angles of 90 and 30 degrees. What is the third?
60 degrees
All three must add to 180. 90 + 30 is 120, and 180 - 120 leaves 60.
Words to know
- polygon
- A closed shape made of straight sides.
- right angle
- A square corner. Exactly 90 degrees.
- line of symmetry
- A fold line where both halves match exactly.
In the games
You will sort shapes by their sides, say whether an angle is acute, right or obtuse, and estimate the size of a turn.
Skills
- Classify polygons by sides · Class 4
- Acute, right and obtuse angles · Class 5
- Lines of symmetry · Class 5
- Estimate an angle · Class 5
- Rotational symmetry and the turn · Class 6
- Angle sum of a triangle · Class 7
- Triangle inequality and Pythagoras · Class 7
- Angles of a quadrilateral · Class 8
- Lines, angles and a transversal · Class 9
- Congruent triangles · Class 9
- Quadrilaterals and the midpoint theorem · Class 9
- Angles in a circle · Class 9
- Similar triangles and the proportionality theorem · Class 10
- Tangents to a circle · Class 10
By class
Class 3 shapes and angles (2) · Class 4 shapes and angles (8) · Class 5 shapes and angles (11) · Class 6 shapes and angles (6) · Class 7 shapes and angles (21) · Class 8 shapes and angles (8) · Class 9 shapes and angles (28) · Class 10 shapes and angles (11)
Practise shapes and angles in Tivumo
No download, no account for your child. Classes 3 to 12, more than 1,000 games.