square = a ²

rectangle = ab

parallelogram = bh

trapezoid = h/2 (b₁ + b₂)

circle = pi r ²

ellipse = pi r₁ r₂

triangle = (1/2) b h

equilateral triangle = [(3)/2] a ² = (3/4) a ²

triangle given SAS = (1/2) a b sin C

triangle given a,b,c = [s(s-a)(s-b)(s-c)] when s = (a+b+c)/2 (Heron's formula)

Volumes

cube = a ³

rectangular prism = a b c

irregular prism = b h

cylinder = b h = pi r ² h

pyramid = (1/3) b h

cone = (1/3) b h = 1/3 pi r ² h

sphere = (4/3) pi r ³

ellipsoid = (4/3) pi r₁ r₂ r₃

Surface Area

cube = 6 a ²

prism:
    (lateral area) = perimeter(b) L
    (total area) = perimeter(b) L + 2b

sphere = 4 pi r ²