Lesson 10 of 20 · 3 moves
The Root of Three
Draw the vesica and join its two crossings.
Let AB be one unit. The height of the vesica, from crossing to crossing, is √3: a number no fraction can equal.
The ancients called such lengths incommensurable. Geometry holds them exactly where arithmetic cannot.
The app snaps to every crossing, checks your construction exactly, and offers hints one move at a time.
Step by step
Circle centred on A through B.
Circle centred on B through A.
Join the two crossings.
What it shows
Measure it: the axis is √3 times AB. The vesica’s proportions, 1 : √3, are the ratio of its width to its height.
