Introduction
(1) Section (Ratio) Formula
(2) Distance between 2 points AB
(3) An equation in x, y, z  represents a surfaces
(a) Ax + By + Cz + D = 0
(b) y = x
(c) y = 0 xz plane
x = 0 yz plane
z = 0 xy plane
(d) x2 + y2 = 1 a cylinder
(e) (x - xo)2 + (y - yo)2 + (z - zo)2 = 1 a sphere
(4) Equation of straight line