I'm surprised no one mentioned Manio and the megalith in Carnac, France, about three or four hundred kilometers south of Stonehenge. At the Quad of Manio there's a precisely measured 3/4/5 right triangle, GDE, sides about 30, 40 and 50 meters, with each vertex marked with a stone. D is the right vertex, the Dame of Manio, a pregnant form. G is the Giant of Manio, a very male 6.5 meter tall stone. E is the rather female Entrance to the Quad of Manio. The legs DE and DG are oriented in the compass directions, 40 meter D to G due east, 30 meter D to E due north.
The site is thought to be ancient family planning. On sunrise of the winter solstice, the shadow of the Giant lands on the Entrance; that's the signal for the party to start. On sunrise of the autumn equinox, the sun rises due east, and the shadow of the Giant falls on the Dame, and baby is born.
The math problem is to determine the latitude of Manio, where (under all the ideal assumptions you can make) the winter solstice sunrise would cast a shadow along the hypotenuse of a 3/4/5 triangle whose legs are in the compass directions.
I'm surprised no one mentioned Manio and the megalith in Carnac, France, about three or four hundred kilometers south of Stonehenge. At the Quad of Manio there's a precisely measured 3/4/5 right triangle, GDE, sides about 30, 40 and 50 meters, with each vertex marked with a stone. D is the right vertex, the Dame of Manio, a pregnant form. G is the Giant of Manio, a very male 6.5 meter tall stone. E is the rather female Entrance to the Quad of Manio. The legs DE and DG are oriented in the compass directions, 40 meter D to G due east, 30 meter D to E due north.
The site is thought to be ancient family planning. On sunrise of the winter solstice, the shadow of the Giant lands on the Entrance; that's the signal for the party to start. On sunrise of the autumn equinox, the sun rises due east, and the shadow of the Giant falls on the Dame, and baby is born.
The math problem is to determine the latitude of Manio, where (under all the ideal assumptions you can make) the winter solstice sunrise would cast a shadow along the hypotenuse of a 3/4/5 triangle whose legs are in the compass directions.