Part i) Calculate the distance between A and B. Given AC = 78m and BC

The bearing of B from C is $254^\circ$.
The bearing of A from C is $344^\circ$.
The angle $\angle ACB$ is the difference between these two bearings:

Since $\angle ACB = 90^\circ$, $\triangle ABC$ is a right-angled triangle with the right angle at C.
Given $AC = 78$ m and $BC