What does it mean when X and Y are directly proportional or indirectly proportional?
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What is probably meant by directly proportional is that x and y grow "with each other". For example, in the equation y = 5x, when x =1, y = 5. If you make x bigger, say, x = 10, then y also gets bigger (in this case, y = 50).
Indirectly proportional (which is sometimes called inversely proportional), is just the opposite. For example, if y = 1/x, then if x = 2, then y = 1/2. If we make x bigger, like x = 4, then y = 1/4, so y is getting smaller. The numbers x and y are related, because they both appear in the equation (this is why they are called proportional), but they grow in different directions.
Indirectly proportional (which is sometimes called inversely proportional), is just the opposite. For example, if y = 1/x, then if x = 2, then y = 1/2. If we make x bigger, like x = 4, then y = 1/4, so y is getting smaller. The numbers x and y are related, because they both appear in the equation (this is why they are called proportional), but they grow in different directions.