Question

If one term of a proportion is not known, what can be used to find the value of that term?

Answer 1

We have to multiply the extreme terms and the middle terms.

For eg.
x : 8 : : 5 : 40
x*40 8*5

40x = 40

Then we have to bring the constant from the LHS to the RHS.

x = 40 ÷ 40
x = 1

Therefore, the equation was :

1 : 8 : : 5 : 40