SAT: Ratios and direct/indirect proportion Quiz
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Ratios describe the relationship between two or more values. Put another way, ratios are fractions, either part-to-part or part-to-whole. So the relationship 1 to 2 can be written as or 1 : 2. You could say that for every 1 of these there are 2 of those. That is a part-to-part ratio. You could also say that for every 1 of these there are 3 of these-and-those. That is a part-to-whole relationship.
A direct relationship between two values means that if one of them is, for example, doubled, so is the other one. If one is halved, so is the other one. If x and y are directly proportional, this can be expressed as y = kx for some constant k.
An inverse relationship between two values means that if one of them is, for example, doubled, the other is halved. If one is multiplied by 3, the other is divided by 3. If a and b are inversely proportional, this can be expressed as for some constant k.
Ratios describe the relationship between two or more values. Put another way, ratios are fractions, either part-to-part or part-to-whole. So the relationship 1 to 2 can be written as or 1 : 2. You could say that for every 1 of these there are 2 of those. That is a part-to-part ratio. You could also say that for every 1 of these there are 3 of these-and-those. That is a part-to-whole relationship.
A direct relationship between two values means that if one of them is, for example, doubled, so is the other one. If one is halved, so is the other one. If x and y are directly proportional, this can be expressed as y = kx for some constant k.
An inverse relationship between two values means that if one of them is, for example, doubled, the other is halved. If one is multiplied by 3, the other is divided by 3. If a and b are inversely proportional, this can be expressed as for some constant k.