Let's solve plane figures problems!
Once you have completed the basic questions from Stage 1 to Stage 4,
try to solve the challenging problems on the Final Stage !
If you can't solve a ploblem, you can check the hint of the question or ask the answer to your friends via Twitter.
'Angles?' contains following contents:
-The sum of the Angles of a triangle
-Exterior angle of a triangle
-The sum of the Angles of a quadrilateral
-The sum of the Angles of a polygon
-Alternate segment theorem
Fix some bugs.