Corner Carnival
A right angle is the opening made by a quarter-turn. It measures 90° and often looks like the corner of an L. Turn the whole L in any direction: it is still a right angle.
Before you try
How can one L-shaped reference help you sort many different angles?
Try it out
Interactive activity
Sign in to play
Use a Google account (yours or a parent’s) to unlock this simulator. We store only your name and email so your favourites and progress follow you.
Signing in needs an internet connection. Once you are signed in, simulators also work offline.
Free preview
Loading controls…
What happened?
Move a control to see what changes and why.
The game practises one idea at a time with simple drawn pictures. Check the same idea with real objects and your NCERT textbook (Chapter 2: Shapes and Angles, pages 21–23).
Something went wrong
This simulator could not load. Check your connection and try again.
Try these ideas
- Make two different acute openings.
- Rotate a right-angle drawing.
- Compare an obtuse opening with a straight line.
Why it works
A right angle is the opening made by a quarter-turn. It measures 90° and often looks like the corner of an L. Turn the whole L in any direction: it is still a right angle.
An acute angle is greater than 0° and smaller than 90°. An obtuse angle is greater than 90° but smaller than 180°. The word “more” needs care: a straight angle of exactly 180° is not obtuse. Look at the shaded opening to decide which angle the picture asks about.
There is only one right-angle size, but many acute and obtuse sizes. A 30° angle and a 70° angle are both acute. Sketch an Angle accepts different valid openings in the requested family. A near-right drawing is snapped to exactly 90°, so the finished corner remains mathematically correct.
Worked example: Sort 45°, 90° and 135°. 45° is below 90°: acute. 90° is exactly the reference: right. 135° is above 90° and below 180°: obtuse.
Check your understanding
Question 1 of 2
An angle measures 120°. Its family is…
Which number is a right angle?
Explain it in your own words
What changed? Why did it happen? Where might you notice this in everyday life?
For parents & teachers
- Colour a picture · 8 minutes. Draw a house and some straight branches. Mark selected openings, then use three colours to classify them.
- Family challenge · 5 minutes. Name an angle family. Ask for two examples, then ask why two different right-angle sizes are impossible.