Arrange the numbers 1 to 19 on a target so every line of three adds up the same
An archery target is marked out with the numbers 1 to 19, one ring and radius at a time, forming twelve straight lines of three numbers each — some along the rings, the rest radiating out from the centre. Can you place the numbers so that every one of those twelve lines adds up to the same total?
Reveal the answer
Yes — every line can be made to total 23. Dudeney's original arrangement places the numbers so all twelve lines of three (six around the rim, six spoking inward) share that same magic sum. From Henry Dudeney's The Canterbury Puzzles (1907).
— Henry Dudeney, The Canterbury Puzzles — 1907, 'The Archery Butt'