wikiHow Proportions Calculator To solve a proportion, you need to find the value of one variable in terms of another variable. A proportion is a statement that two ratios are equal, so you can use cross-multiplication to solve for the unknown variable. The formula for solving a proportion is: a/b = c/d => a = (b x c) / d Here are the steps to solve a proportion using a calculator: 1. Enter the values of the known ratios into the calculator, separating them by commas. 2. Determine which variable you want to solve for. 3. Apply the formula for solving a proportion, using the values you entered and solving for the unknown variable. 4. Enter the values into the calculator and solve. For example, let's say you have the proportion 2/3 = x/12. To solve for x using a calculator, you would follow these steps: 1. Enter the values of the known ratios into the calculator: 2, 3, 12. 2. Determine that you want to solve for x. 3. Apply the formula for solving a proportion, using the values you entered and solving for the unknown variable: 2/3 = x/12 => x = (2 x 12) / 3 4. Enter the values into the calculator and solve: x = 8. So the value of x in the proportion 2/3 = x/12 is 8. Page