The people of Bridgetown wanted to build a bridge across a nearby river. Since they were poor swimmers, their master Trigonomos
agreed to measure the width of the river without actually crossing it. Trigonomos spotted a tree across the river and marked the spot directly across from it. Then he walked to another point 15 meters down the river and found that the angle between his side of the river and the line connecting him to the tree was 76?, degree . What is the width of the river?
The width of the river is the side of a right triangle opposite the angle of 76°. The 15 m distance is the length of the side adjacent to the measured angle. So, we have ...
