This site introduces problems of Sansue, i.e. mathematics which Japanese schoolchildren learn at elementary school. Problems are selected mainly from entrance examinations of famous junior high schools for 6th grade Japanese schoolchildren (12 years old) to take. We found Sansue is not only one of subjects at school but one of Japanese culture. Please enjoy Japanese Sansue culture.
As shown in a figure, there are a circle which touches inner side of the square 10 cm one side and a square whose each vertex is on the circumference. Find the area of the inside square.
