Enter the values and calculate your proportion using the formula a:b=c:d, for example 4:3=100:X ⇒ X=(3×100)/4.
In mathematics, a proportion is the equality between two ratios. In other words, it is a relation that establishes an equivalence between four quantities, called terms, which are proportional to each other.
The fundamental property of proportions states that the product of the means is equal to the product of the extremes.
If a:b=c:d, then a×d=b×c.
A practical case: we have an image 100 cm wide and we need to calculate the height, proportional to 4:3; how tall will the image be?
To calculate it we should perform the following operations:
4:3=100:X
X=(3×100)/4
X=75
Therefore the image will be 75 cm tall.
In mathematics, considering the proportion: 4:3=100:75
3×100=300
4×75=300
Since the two products are equal to 300, the proportion is valid!