Robot Yoga
In an elbow picture, the elbow is the vertex. The upper arm and forearm are the two arms of the angle. The opening is measured between them, not between the forearm and the edge of the screen. A small shaded mark shows which opening to use.
Before you try
Where is the angle when a robot bends its elbow?
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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 23).
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Try these ideas
- Draw a 60° elbow and a 120° elbow.
- Identify the vertex before drawing.
- Sketch a knee angle on paper using two straight segments.
Why it works
In an elbow picture, the elbow is the vertex. The upper arm and forearm are the two arms of the angle. The opening is measured between them, not between the forearm and the edge of the screen. A small shaded mark shows which opening to use.
If the upper arm stays still and the forearm turns, the elbow opening changes. It can be acute, right or obtuse. Moving the entire stick figure without changing its pose does not change that opening.
Pose Pencil leaves one forearm missing. Draw it to complete the requested angle, starting at the elbow. A correct stroke is straightened and aligned to the target. These are angle sketches: the goal is to read the geometry, rather than copy a difficult physical pose. The same reasoning works with two straight leg segments meeting at a knee.
Worked example: An upper arm points left and the forearm points straight up. What is the elbow angle? Place the vertex at the elbow. Compare the left-pointing arm and upward-pointing arm. Their smaller opening is a right angle, 90°.
Check your understanding
Question 1 of 2
The vertex of the elbow angle is the…
A 135° elbow opening is…
Explain it in your own words
What changed? Why did it happen? Where might you notice this in everyday life?
For parents & teachers
- Stick-figure postcards · 8 minutes. Draw three simple figures with acute, right and obtuse elbow openings. Label each joint and its two arms.
- Partner instructions · 5 minutes. Describe an arm opening without showing your sketch. Let a partner draw it and compare the marked angle.