Angles
Start by reading a protractor that is drawn for you, then move on to the rules that let you work out an angle you cannot measure.
No account, and the maths stays in your browser — more— less
This activity is for learning and practice. Anything it suggests is indicative only — it is not a formal assessment and not a substitute for a teacher or tutor.
Nothing you answer is sent to Zerdly. Progress is saved on this device only if you switch saving on, and you can delete it at any time. How Kids Maths handles data.
Set your country and age — change
Setting an age keeps the questions at the right level for that age. It does not lock anything — you can still try any topic, at any age, in any order. Levels are a guide only, not a curriculum.
Your age is not saved anywhere. Your country is remembered only if you have switched saving on.
Saving your progress
Nothing is being saved. You can practise as much as you like — when you close the tab, the session is gone.
An angle is an amount of turn
Not a corner, and not how long the arms are. A quarter turn is 90° and we call it a right angle; half a turn is 180° and looks like a straight line; all the way round is 360°. Everything else in this topic comes from those three.
Three rules worth knowing by heart
- On a straight line: 180°. Two angles sitting on a line always add to a half turn.
- Around a point: 360°. Angles that meet at a point and fill the space add to a whole turn.
- In a triangle: 180°. Always, for every triangle, however stretched or squashed it looks.
Mixing up the first two is the most common mistake here — 180 and 360 are easy to swap. It helps to picture the turn: a straight line is only halfway round.
Angles get turned too
A right angle drawn with one arm lying flat along the bottom is easy to spot. Rotate the whole thing and many people stop recognising it, because they learned the picture rather than the turn. So the angles here are drawn at all sorts of orientations.
School levels
School levels are a guide only. They show where a skill is usually taught in each country and are not taken from, aligned to, or endorsed by any curriculum authority. Your school may cover it earlier or later.