Tangent at a point

Draws the tangent to a circle at a point on it. Ruler and compass only.

All parts

Part 1 of 3: Rule the radius to the pointStep 1 of 2Ruler

The tangent at A is at right angles to the radius there. Lay the ruler so its edge passes through O and A.

Keys: left and right arrows step, Space plays or pauses, Escape goes back to all constructions.