Given the line segment AB = 2cm, extend AB to point C to make AC = 3AB, and extend AB to point d reversely to make ad = 1 / 2Ab. Find the fraction of line segment BD to BC

Given the line segment AB = 2cm, extend AB to point C to make AC = 3AB, and extend AB to point d reversely to make ad = 1 / 2Ab. Find the fraction of line segment BD to BC

Because ad = 1, ab = 2, BD = 3cm
So BD / BC = 3 / 4
That is to say, the length of segment BD is 3 / 4 of BC