Question 18
Rabbit wants to row across the river to visit Squirrel but does not know the river’s width. Clever Rabbit devises a way to measure it while staying on his own bank. First he drives a stake at a point called A, as shown.
Rabbit stands at A and looks towards the tree across the river, calling its position P. From that direction he turns 90°, parallel to the riverbank, and walks straight to any point, where he drives a second stake B. He continues straight beyond B until his distance from B equals AB, then drives stake C. From direction CB he turns 90° and walks until stake B lines up with P, where he drives stake D. Rabbit measures CD = 10 m and uses it to calculate AP, the river’s width. How wide is the river?
Rabbit stands at A and looks towards the tree across the river, calling its position P. From that direction he turns 90°, parallel to the riverbank, and walks straight to any point, where he drives a second stake B. He continues straight beyond B until his distance from B equals AB, then drives stake C. From direction CB he turns 90° and walks until stake B lines up with P, where he drives stake D. Rabbit measures CD = 10 m and uses it to calculate AP, the river’s width. How wide is the river?