Geometry 2 Dimensional Shapes

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

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

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

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

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

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.

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

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

Summary of Polygons polygons and characteristics

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