A point O is at the top of a vertical cliff. The angle of elevation of O from a boat which is at a point A due South of O is 28°. The boat now sails 50 metres due North to a point B from which the angle of elevation of O is 70°. Find, to the nearest metre, the distance of B from the foot of the cliff.
<img src="../../..//assignments/uploaded_files/static/bb/bb/bbbb6df4fed880c2bdcb3f5e94bda2a6.png" title="" alt=""> We have the following picture. Express h from left side and right side triangles: h = a tan 70 = (50-a) tan 28,