Question

PLEASE HELP! A competition: knowing that a/b = c/d , make as many different proportions that involve a, b, c, and d as you can.

Answer 1

Answer:

• a/b = c/d
• a/c = b/d
• b/a = d/c
• c/a = d/b

Step-by-step explanation:

The possible proportions can be formed by dividing the equation ...

  ad = bc

by any of the four products that consist of one left-side variable and one right-side variable.

Dividing by ab gives ...

  d/b = c/a

Dividing by ac gives ...

  d/c = b/a

Dividing by bd gives ...

  a/b = c/d

And dividing by cd gives ...

  a/c = b/d

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Comment on writing proportions

Any proportion can be written in any of these four ways. It is generally convenient to choose the one that has the unknown variable as a numerator with a denominator of 1 (if possible).