# Ratio and Proportion Formulas

As you know Ratio is a relation between two quantities or number , and proportion is a ratio of ratios.

Here are some basic **formulas** related to **Ratio and Proportion** in mathematics:

**Ratio and Proportion formulas**:

1> A ratio of “a” and “b” is denoted by a:b and is read as: “a is to b”.

in a ratio the first part ( “a” in our example ) is called Antecedent and second part ( “b” in our example ) is called Consequent.

2> A duplicate ratio is the ratio of second degree of the original ratio. For example the duplicate ratio of is

3> A triplicate ratio is the ratio of third degree of the original ratio. For example the triplicate ratio of is

4> A sub-Duplicate ratio is the ratio of half degree of the original ratio. For example the sub-duplicate ratio of is

5> A sub-triplicate ratio is the ratio of one third degree of the original ratio. For example the sub-triplicate ratio of is

6> The ratio obtained by multiplying two or more ratios term wise is called compounded ratio.

for example compounded ratio of ratios , , is

7> The ratio obtained by adding two or more ratios term wise is called “Addendo”.

for example Addendo ratio of ratios , , is

7> A proportion of ratios “a:b” and “c:d” is denoted by: a:b :: c:d

where “a” and “d” are called Extremes and “b” and “c” are called means.

8> If in a proportion a:b :: b:c :: c:d , then the proportion is said to be a continued proportion of a , b, c &d.

9> If a:b :: b:c :: c:d or is a continued proportion then,

c = dk , b=ck=dk^{2} and a=bk=ck^{2}=dk^{3}

10> A proportion a:b :: c:d or can also be re-written as:

a> and is called “Invertendo”.

b> and is called “Alternando” .

c> and is called “Componendo”.

d> and is called “Dividendo”.

e> and is called “Componendo and Dividendo”.

Related posts:

- Algebraic Formulas Algebra is one of the most basic part of mathematics...
- Derivative of simple algebraic or polynomial functions. The derivative and calculations on finding derivative of simple algebraic functions...
- Derivatives of Trigonometric functions. As you know, The functions SINE x(sin x) , CO-SECANT...
- Infinitesimals and Differentials. What is Infinitesimals and Differentials. A complete guide for understanding...