if it has 3 sides, its a triangle; 4 sides is a quadrilateral (rectangle, square, rhombus, parallelogram, trapezoid, kite, etc.) 5 a pentagon, 6 a hexagon, 7 is a heptagon, 8 is an octagon, 9 nonagon, 10 is a decagon, and so on. if all sides and angles are congruent, then it is regular.