Formulas

 

Area of a triangle = ab / 2

 

Area of a parallelogram = ab

 

Area of a trapezoid = a ( (b+c) / 2)

 

Area of a regular polygon = # of sides ( (side length x bisector length) / 2)

 

Area of a circle = p  x  radius2

 

Surface area of a cylinder = 2 (area of base) + 2 (p  x  radius x height)

 

Surface area of a sphere = 4 p radius²

 

 

Surface area of a rectangular prism =

2 (width x height) + 2 (height x depth) + 2 (width x depth)