A biologist wants to know the width of a river in order to properly set instruments for studying the pollutants in the water. From point A which is straight across the river from point C, the biologist walks downstream 70 feet to Point B and sights to point C. From this sighting, it is determined that θ = 54º. How wide is the river to the nearest foot?

Guest Oct 28, 2017

If you draw a picture of his path, it looks like this..



It makes a right triangle, and side AC is the width of the river. In every right triangle,


tan θ  =  opposite / adjacent


tan 54°  =  AC / 70                   Multiply both sides by  70 .


70 tan 54°  =  AC


96 feet  ≈  AC

hectictar  Oct 28, 2017

8 Online Users

New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.