C. 821. A unit square ABCD is rotated about its vertex C through 90o. Determine the area swept out by the side AB.
Google Translation (Sorry, the solution is published in Hungarian only.)
Statistics on problem C. 821. 608 students sent a solution.
5 points:437 students.
4 points:44 students.
3 points:23 students.
2 points:9 students.
0 point:50 students.
Unfair, not evaluated:45 solutions.