The illustration shows the figure known in mathematics as;
Tales' sails
Pythagorean sickles
Archimedes' arches
lune of Hippocrates,
In geometry, the lune of Hippocrates, named after Hippocrates of Chios, is a lune bounded by arcs of two circles, the smaller of which has as its diameter a chord spanning a right angle on the larger circle. Equivalently, it is a non-convex plane region bounded by one 180-degree circular arc and one 90-degree circular arc. It is the first curved figure to have its exact area calculated mathematically.
reach: rather globalgeometrymathematics
Answers by country
Tales' sails
Pythagorean sickles
Archimedes' arches
lune of Hippocrates,
answers
the Netherlands
12
Australia
19
India
33
the United Kingdom
37
Switzerland
13
Poland
1888
Germany
106
the United States
45
Austria
32
Greece
12