1. Geometry
2 Dimensional Shapes

2. Polygon
Simple, closed figure made up of line segments which intersect in exactly two places
Regular polygon: all sides are equal
all interior angles are
equal
Quadrilateral: polygon with 4 sides

3. Parallelogram 2 pair of parallel sides Area = base x height A = bh

4. Trapezoid One pair of parallel sides Area = height x (base 1 + base 2)
A = h(a+b) a
Height b

5. Rectangle Interior angles are all 90 ̊ Area = length x width A = lw

6. Square
Rectangle with 4 equal sides
Area = side x side
A = s2

7. Rhombus
4 equal sides
Area: The area of a rhombus is A= (1/2) d1 * d2 , where d1 is the length of the first diagonal and d2 is the length of the second diagonal.

8. Triangles: 3 sided polygon
Right: has a 90 ̊ angle
Equilateral: equal sides
Isosceles : 2 equal sides
Scalene: no equal sides

9. All triangles Area = ½ base x height A = ½ bh height height base base
Right triangles: a2 + b2 = c2

10. Summary of Polygons
polygons and characteristics

11. Circle
Set of all points in a plane that are a fixed distance from a given point (the center)
Area = pi x radius squared
Area= ∏r2
Perimeter = circumference
P = 2Πr
Radius