A regular hexagon has vertices A, B, C, D, E and F (labelled anticlockwise).

Vertices A and D have coordinates A (9, 11) and D (-1, 1).

Find OB, the exact distance from the origin to vertex B.

Depending on your method, you may find it helpful to know that tan 75^o = √3 + 2, but there are ways to do this problem that do not require this.

Thanks to KCLMS alumna Olive for the idea behind this challenge.