Question

How can you use an equation to find an unknown value in a proportional relationship?

Answer 1

"1) Identify the known ratio, where both values are known.

2) Identify the ratio with one known value and one unknown value.

3) Use the two ratios to create a proportion.

4) Cross-multiply to solve the problem."

Answer 2

Well if you already know how to write an equation for a given set of proportions, then all you have to do is replace the unknown value with x, and then cross multiply and solve the equation. One important thing to remember is that for each proportion the numerator and the denominator have to be of the same units in the equation.