· Ratio is nothing but comparison of quantities.
· A proportion is a name we give to a statement that two ratios are equal.
It can be written in two ways:
· Two equal fractions,
· Using a colon, a:b = c:d
· When two ratios are equal, then the cross products of the ratios are equal.
· That is, for the proportion, a:b = c:d , a x d = b x c
If A:B = 2:3 & B:C = 5:7 , then A:B:C = ?
Points to Remember:
a : b : : c : d
a : b = c : d
ad = bc
· Fourth Proportion d = bc/a
· Third Proportion c = b2/a
· Second Proportion b = Mean Proportion = √ca
· There is no formula for First Proportion ,Hence no question would be asked based on first proportion.