6th Class Mathematics Ratio and Proportion Ration and Proportion

Ratio and Proportion

• Ratio is a method of comparing two quantities of the same kind by division.

• The symbol used to represent a ratio is: and is read as 'is to'.

• A ratio can be expressed as a fraction.

• A ratio is always expressed in its simplest form.

• A ratio does not have any unit, it is only a numerical value.

• A ratio consists of two terms. The first term is called the antecedent and second term is called the consequent.

• A ratio can be written in its simplest form by dividing the antecedent and consequent by their H.C.F.

• The antecedent and consequent of a ratio cannot be interchanged. The order of terms in a ratio is important.

• To express two terms in a ratio they should be in the same units of measurement.

• When two ratios are equal they are said to be in proportion. The symbol for proportion is:: and is read as 'is as to'.

• The two terms in the middle of a proportion are called means and the first and last terms are called extremes.

• If two ratios are to be equal or to be in proportion, their product of means should be equal to the product of extremes.

• If a : b :: c : d then the statement ad = be is true.

• If a : b and b: c are in proportion such that b2 = ac then b is called the mean proportional of a : b and b : c.

• We can get equivalent ratios by multiplying or dividing the antecedent and consequent of a ratio by the same number.

• Unitary method: The method in which we find the value of one unit first and then the value of required number of units is called the unitary method.