Deriving the 90 degree anticlockwise rule
Mathematics · Grade 10 · about 40 minutes
A quarter-turn anticlockwise about the origin sends (x, y) to (-y, x). Build it from a plotted point, not from memory.
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- 9 sections of explanation, worked examples and diagrams
- 1 practice task with hints and worked answers
- A quiz that marks itself as you go
- Your progress kept across every subject you take
Other lessons in this sub-strand
- Rotating a figure
- Rotational symmetry
- Deriving the 90 degree anticlockwise rule
- 90 degrees clockwise and 270 anticlockwise
- Half-turns of 180 degrees
- Rotation about a point that is not the origin
- Finding the centre of rotation
- Finding the angle and the direction
- Inverse rotations and combining turns
- Rotational symmetry in the environment