In order to solve the terms which are given in the proportion, we Mean that:
a) a, b, c and d are called first, second, third and the fourth terms of the proportion.
b) Here in proportion we say ‘a’ and ‘d’ are the extremes or we say them as extreme terms and ‘b’ and ‘d’ are called the mean terms or we also call them the means.
c) We must always remember that in case of proportions, we must have product of means = product of extremes.
d) We also call d as the fourth proportion to the terms a, b, and c terms.
e) In case we are given a: b:: b : c, then a, b, and c are said to be in continued proportions.
f) Here we call ‘c’ as the third proportion to ‘a’ and ‘b’ also we say that ‘c’ is the fourth proportion to a, b, b.
g) Also the Point to be remembered in this continued proportion is that a/b = b / c.
Thus we say that b2 = a * c,
Or we say that b = root (a * c).