Polygon

1. other polygons

1.1. pentagon

1.1.1. 5 sides

1.2. hexagon

1.2.1. 6 sides

1.3. heptagon

1.3.1. 6 sides

1.4. octagon

1.4.1. 8 sides

2. Triangle

2.1. sides

2.1.1. Equilateral triangle

2.1.1.1. all sides are equal

2.1.2. isosceles triangle

2.1.2.1. two sides are equal

2.1.3. scalene triangle

2.1.3.1. no sides are equal

2.2. angles

2.2.1. acute angled triangle

2.2.1.1. all angles are less than 90

2.2.2. right angled triangle

2.2.2.1. one angle = 90

2.2.3. obtuse angled triangle

2.2.3.1. one angle > 90

3. Quadrilaterals

3.1. Trapezium

3.1.1. exactly one pair of opposite sides are parallel

3.2. Parallelogram

3.2.1. rectangle

3.2.1.1. square

3.2.2. rhombus