Sangaku Pentagon and 6 Triangles
Sangaku Pentagon and 6 Triangles
Sangaku from the Miyagai prefecture, circa 1912.
6 congruent right triangles fan out along the sides
of a regular pentagon of side a.
Find the length of the hypotenuse t of these triangles
in terms of a. (Jill Vincent & Claire Vincent)
http://geometricloci.tumblr.com/post/104611688637/sangaku-problems
http://www.hermay.org/jconstant/wasan/sangaku/index.html