LEARN MATH STEP BY STEP THROUGH VERY EASY PROCESS

CROSS PRODUCT RULE OF PROPORTION

__CROSS PRODUCT PROPORTION__

**Suppose, w, x, y, and z are the 1 ^{st}, 2^{nd}, 3^{rd}, and 4^{th}
terms of the proportion respectively then the equation would be w : x =
y : z . The 1^{st} & 4^{th} terms are called EXTREMES and the 2^{nd} & 3^{rd} terms are called MEANS.**

**The term z is considered as a 4 ^{th} and also called the Fourth Proportional to w, x, y.**

** 1 ^{st} Term 3^{rd} Term w y**

** So, ------------ = ------------ ; -------- = -------- **

** 2 ^{nd} Term 4^{th} Term x z**

** If we multiply
both the 1 ^{st} Term X 4^{th}
Term = 3^{rd} Term X 2^{nd} Term ; so, wz = yx**

** The above process is
called the cross product rule. **

**If four numbers w, x, y, & z are in proportion of which any three is known,
we can know the remaining unknown number by using the fact that wz = yx .**

** If four numbers are
in proportion then **

**We can conclude that, the product of the EXTREMES = the product of the MEANS**

**The** **a****bove rule helps us to find any term of proportion if any three are known to us.**