\(A=\pi r^2,\;C=2\pi r\)
Circle
\(A=\tfrac{1}{2}bh\)
Triangle
\(c^2=a^2+b^2\)
Pythagorean Theorem
30-60-90: \(x,\,x\sqrt{3},\,2x\)
Special Right △
45-45-90: \(s,\,s,\,s\sqrt{2}\)
Special Right △
\(V=lwh\)
Rectangular Solid
\(V=\tfrac{4}{3}\pi r^3\)
Sphere
\(V=\tfrac{1}{3}\pi r^2h\)
Cone
\(V=\tfrac{1}{3}lwh\)
Pyramid
Circle: 360°. Circle: 2π radians. Triangle angles sum to 180°.