1. linee perpendicolari   pentagon   vertex   perpendicular lines   quadrangle   Hint Half-n-half Clue   2. piano   edge   hemisphere   quadrangle   plane   Half-n-half Clue   3. quadrangolo   quadrangle   edge   hemisphere   segment   Half-n-half Clue   4. quadrilateral   quadrilateral   concave   edge   ellipse   Half-n-half Clue   5. losanga   concave   parallelogram   ellipse   rhombus   Half-n-half Clue   6. ellisse   parallel lines   ellipse   vertex   polygon   Half-n-half Clue   7. pentagono   segment   oval   hemisphere   pentagon   Half-n-half Clue