Based on Angles :
1)Acute angled triangle - All the angles are acute angle
2)Right angled triangle - 1 angle is right angle
3)Obtuse angled triangle - 1 angle is obtuse angle
Based on sides :
1)Equilateral triangle - All sides and angles are equal
2)Isosceles triangle - Only 2 sides are equal and angles opposite to the equal sides are equal
3)Scalene triangle - No Sides are equal
1) Trapezium - Diagonals intersect each other.
Line joining the midpoints of the non parallel sides is parallel to either of th two parallel sides .
2) Parallelogram [ Square , Rectangle and Rhombus come under parallelogram] - Opposite sides and angles are equal .
Diagonals of a parallelogram bisect each other .
3) Kite - Has 2 pairs of adjacent sides equal .