Problem Find the diameter of a circle inscribed in a triangle, of which sides have lengths of $21, \ 17$ and $10 \ inches$. $$ $$ $$ $$ $\downarrow$ $\downarrow$ $\downarrow$ $\downarrow$ $\downarrow$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ Solution Let…

Problem What is the side length of a square with an area of ​​$85000 ft^2$ ? $$ $$ $$ $$ $\downarrow$ $\downarrow$ $\downarrow$ $\downarrow$ $\downarrow$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ Solution The prime factorization of $85000$ is:$$85000=2^3×5^4×17=2^2×5^4×(2×17),$$$$∴ \ \sqrt{85000}=2×5^2×\sqrt{2×17}≒291.547594742265.$$  …

Souzume Hachimangu Shrine is located 1.2 $km$ west-southwest of Kibitsu Station on the JR Kibi Line. Problem The contents are unknown as some parts are illegible.     Reference Yoshikazu Yamakawa, ed. (1997) Okayama ken no Sangaku (Sangaku in Okayama Prefecture), p.27; p.400.