Jean camps beside a wide river and wonders how wide it is. She spots a large rock on the bank directly across from her. She then walks upstream until she judges that the angle between her and the rock, which she can still see clearly, is now at an angle of 30 downstream. Jean measures her stride to be about 1 yard long. The distance back to her camp is 120 strides.
(a) About how far across, in yards, is the river?
(b) About how far across, in meters, is the river?
Frequently Asked Questions
What scientific concept do you need to know in order to solve this problem?
Our tutors have indicated that to solve this problem you will need to apply the Trig Review concept. You can view video lessons to learn Trig Review. Or if you need more Trig Review practice, you can also practice Trig Review practice problems.
What professor is this problem relevant for?
Based on our data, we think this problem is relevant for Professor Heidarian's class at UMD.