Rotation spins a shape around a fixed point — the centre of rotation — by an angle, clockwise or anticlockwise. Like a hand sweeping around a clock face.
Turn the shape
Turn: 90°
original image
The three things a rotation needs
- A centre — the pivot point. It's the only point that stays still.
- An angle — how far to turn (90°, 180°, 45°…).
- A direction — clockwise or anticlockwise (anticlockwise is the positive direction in maths).
- Everything else: lengths, angles, area and orientation are all preserved — the image is congruent and *not* mirrored.
Your turn
Rotate the point (4, 0) by 90° anticlockwise about the origin. Where is it now?
Two reflections in intersecting lines = one rotation about the crossing point, through twice the angle between the lines. Spin the slider above to 360° and the image lands exactly back on the original.