There are certain skills that you absolutely need to survive in math: order of operations, the distributive property, the ability to solve for a variable, creating equivalent fractions, and solving proportions. When you have a handle on these skills, most math should be within your grasp.
Today, we’re going to focus on the overly useful proportions. Proportions help you solve percent, metric conversions, scale, and unit price problems. The basic appearance of your standard proportion equation looks like this:
To start solving, you cross-multiply and set the products equal to each other.
ad = bc
From here, you divide both sides of the equation by whatever number is sitting beside the variable you’re solving for. For example, if you were solving for a, then the resulting equation would look like: a = (bc)/d.
[...] measure of the side you already know, and place a variable over the side you need to know. Then you solve it like a proportion, just as you did with the 45-45-90 [...]
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