Geometry

&larr; back to Guerilla Engineering

Areas
square = $$a^2 $$

rectangle = $$ab $$

parallelogram = $$bh $$

trapezoid = $$h/2 (b1 + b2) $$

circle = $$ \pi\ r^2$$

ellipse = $$ \pi\ r_1 r_2$$

triangle = $$\frac{1}{2}(bh)$$

equilateral triangle = $$\frac{\sqrt{3}}{4}(a^2)$$

triangle given SAS = $$ \frac{1}{2}a b \sin C$$

Volumes
cube = $$a^3 $$

rectangular prism = $$a b c $$

irregular prism = $$b h $$

cylinder = $$b h = \pi\ r^2 h $$

pyramid = $$\frac{1}{3} b h $$

cone = $$\frac{1}{3} b h = \frac{1}{3} \pi\ r^2 h $$

sphere = $$\frac{4}{3} \pi\ r^3 $$

ellipsoid = $$\frac{4}{3} \pi\ r_1 r_2 r_3$$

Surface Areas
cube = $$6 a^2$$

rectangular Prism = $$2ab + 2bc + 2ac$$

sphere = $$4 \pi\ r^2$$

cylinder = $$2 \pi\ r^2 + 2 \pi\ r h$$

Perimeters
square = $$4a $$

rectangle = $$2a + 2b$$

triangle = $$a + b + c  $$

circle = $$2 \pi\ r = \pi\ d$$