Question

. A surveyor wishes to measure the distance across Pasig River. She sets up her transit at a point C on the bank of the river, and sights on a point B on the other bank directly opposite her. Then she turns the transit through a right angle, and measures off a distance of 100 meters to a point A. She moves the transit to A, and measures the angle CAB, which is 50deg 11min 10 sec. How wide is the river?

Answer 1

draw the diagram, and it is clear that the distance x is

x/100 = tan 50°11'10"