LEARN MATH STEP BY STEP THROUGH VERY EASY PROCESS

PROPORTION

__PROPORTION __

**If two ratios w : x and y : z are equal, that is w : x = y :
z then the four quantities w, x, y & z are said to be in proportion. This
is also written as w : x : : y : z, the quantities w, x, y, z which are called
the terms of the proportion, need not all be of the same kind. However the
terms of the first ratio must be of the same kind, and the terms of the second
ratio must also be of the same kind.**

**For your better understanding, we will provide you some
example –**

**Example.1) Show the numbers such as 12, 36, 72, 216 are
in proportion **

**Ans.) As per the given condition 12, 36, 72, 216 are in
proportion because –**

** 12 1**

** -----------
= ---------- = 1 : 2**

** 24 2**

** 72 1**

** And ---------- = --------- =
1 : 2**

** 216 2**

**So, numbers such as 12, 36, 72, 216 are in proportion.**

**Example.2) Show the quantities 4 h, 12 h, 16 L, 48 L are in proportion.**

**Ans.) As per the given condition 4 h, 12 h, 16 L,
48 L are in proportion because –**

** 4 h 1**

** ----------- = --------- =
1 : 3**

** 12 h 3**

** 16 L 1**

** ------------- = ---------- = 1 : 3**

** 48 L 3**

**So, the
quantity such as 4 h, 12 h, 16 L, 48 L are in proportion. **

**The first and
the fourth terms of a proportion are called the “EXTREMES”, while the second
and the third terms are called the “MEANS”. The fourth term is also called the “FOURTH
PROPORTION” to the other three terms.**

** w y**

**If, w : x = y : z, then -------- = -------- or wz = xy**

** x z**

**hence we can
conclude that, the product of the "Extremes" = the product of the "Means"**

**above rule is
known as the “CROSS PRODUCT RULE”.**