1. shikakkei   polygon   quadrangle   ellipse   segment   Hint Half-n-half Clue   2. rankei   edge   oval   parallelogram   quadrangle   Half-n-half Clue   3. totsumen   pentagon   ray   quadrangle   convex   Half-n-half Clue   4. heikoushihenkei   parallelogram   plane   hemisphere   perpendicular lines   Half-n-half Clue   5. takakkei   prism   polygon   perpendicular lines   oval   Half-n-half Clue   6. hankyuutai   pyramid   prism   hemisphere   heptagon   Half-n-half Clue   7. ryoukei、hasuhoukei   parallelogram   plane   rhombus   perpendicular lines   Half-n-half Clue