15. How to Solve the Width of the River Without Crossing It? how to solve the width of the river without crossing it? if you only have a big protractor and a meter stick? Submitted by tartle · Added 29 November 2010 Show Solution Solution: To determine the width of the river without crossing it, first measure a specific distance along the bank using the meter stick. Then, look at a tree or rock directly across the river and use the protractor to measure the angle from your new position to the tree/rock. Using the tangent of the angle, you can calculate the width of the river with the formula: width = distance traveled along the bank * tan(angle).
Comments (1)
Trig if you have line of site.
Look at a tree or rock exactly across, then parallel the river with your meter stick then determine the angle from your new point to the rock/tree.
Tangent of angle = width of river over the length traveled paralleling the river.
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