1. concave   concave   quadrilateral   hexagon   prism   Hint Half-n-half Clue   2. pyramide   oval   vertex   ellipse   pyramid   Half-n-half Clue   3. pentagone   plane   pentagon   prism   polygon   Half-n-half Clue   4. quadrilatère   parallel lines   perpendicular lines   quadrangle   plane   Half-n-half Clue   5. convexe   heptagon   ray   oval   convex   Half-n-half Clue   6. lignes parallèles   oval   rhombus   straight line   parallel lines   Half-n-half Clue   7. plat   vertex   parallel lines   plane   prism   Half-n-half Clue