In a situation of proportionality, the mathematical reasoning
that makes it possible to determine a missing term when you know all of the other terms.
This proportional reasoning
, gave rise to an algorithm called cross multiplication
, which is easy to visualize and to apply.
We used 8 litres of paint to repaint the walls of a room with a surface area of 40 m². How many litres of paint would we need to repaint the walls of a room with a surface area of 60 m²?
||This arrangement leads to the equation:
40x = 8 • 60 by multiplying the terms diagonally.
Therefore, x = 12.