Geometry Area Formulas
Regular Polygon (given apothem)
Area = (1/2) x Apothem x Perimeter
triangle (familiar formula)
Area = (1/2) x base x height
kite
Area = (1/2) x diagonal1 x diagonal2
rhombus
Area = (1/2) x diagonal1 x diagonal2
trapezoid
Area = (1/2) x height x (base1 + base2)
triangle (new formula)
Area = (1/2) x side1 x side2 x sin(angle)
Regular Polygon (given radius)
Area = (n/2) x radius^2 x sin(360/n)
parallelogram
Area = base x height
rectangle
Area = base x height
circle
Area = pi x r^2
segment
Area = sector area - triangle area
circumference
C = pi x diameter
arc length or central angle
angle/360 = arc length/circumference
sector area or central angle
angle/360 = sector area/circle area