a-1. Solving one proportion using properties of equality:
We can use the multiplication property of equality:
[tex]\frac{x}{21}=\frac{4}{7}\Rightarrow21\cdot(\frac{x}{21}=\frac{4}{7})\Rightarrow x=\frac{21\cdot4}{7}\Rightarrow x=3\cdot4\Rightarrow x=12[/tex]
We multiply to both sides of the proportion by 21, and we obtained x = 12.
a-2. In the second proportion, if we using cross products, we have:
And we also have the value x = 12.
b. Imagine that we need to make pizza, and we know that the ratio of flour to water is:
300 gr/100ml water
If we have this ratio, then if we have 1000ml of water, what is the quantity of flour that we need.
x = quantity of flour. Then, we can represent this situation as follows:
Then, we have:
Then, to prepare pizza for 1000ml of water, we will need 3000 grams of flour.
