Lost River Camps

Jean camps beside a wide river and wonders how wide it is....?

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 θ = 45° downstream (see figure). Jean measures her stride to be about one yard long. The distance back to her camp is n = 110 strides. About how far across, both in yards and in meters, is the river?

Public Comments

1. I believe you have the wrong category. I would place this question in Maths.