Henry Ernest Dudeney/Puzzles and Curious Problems/200 - Measuring the River

Puzzles and Curious Problems by Henry Ernest Dudeney: $200$

Measuring the River

A traveller reaches a river at the point $A$,

and wishes to know the width across to $B$.

As he has no means of crossing the river, what is the easiest way of finding its width?

Sources

• 1932: Henry Ernest Dudeney: Puzzles and Curious Problems ... (previous) ... (next): Geometrical Problems: Various Geometrical Puzzles: $200$. -- Measuring the River
• 1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Geometrical Problems: Plane Geometry Puzzles: $306$. Measuring the River