What does a colon mean when dealing with mathematical proportions?

Answer 1

Ratios and proportions Briefly, it means "is to." A double colon -- :: -- means "as." For example, x:10 :: 3:2 can be read "x is to ten as three is to two." Mathematically, that be written in the form of the following equation: x/10 = 3/2. If you cross multiply,1 the equation changes its shape but means the same thing: 2x = 3 * 10,

2x = 30

x = 30/2

x = 15 1. If a ratio, a/b, is equal to another ratio, c/d, then ad = bc. It's called cross-multiplication because you are multiplying the numerator (top) of the first ratio by the denominator (bottom) of the second one, and vice versa, in a sort of a criss-cross pattern.