The area of the room is 15.4 m2, which is 22% of the area of the entire apartment. Find the area of the apartment.

From the condition it is known that the area of the room is 15.4 m2, which is 22% of the area of the entire apartment. In order to find the area of the apartment, we will compose and solve the proportion.
Let’s use the variable x m2 to denote the area of the whole apartment. And let’s take it as 100%.
Now we turn to the proportions.
x m2 room area – 100%;
15.4 m2 apartment area – 22%.
We get the proportion:
x / 15.4 = 100/22;
We need to find the unknown extreme term of the proportion.
x = (15.4 * 100) / 22 = 1540/22 = 70 m2 apartment area.
Answer: 70 m2 apartment area.