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Finding the Fourth Proportional to 1,209.57, 1,669.36 and 685.60

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Solution

The fourth proportional to 1,209.57, 1,669.36 and 685.60 is: 946.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.57 : 1,669.36 = 685.60 : x
  2. Step 2: Convert to fraction form
    1,209.57/1,669.36 = 685.60/x
  3. Step 3: Cross multiply
    1,209.57x = 1,669.36 × 685.60
  4. Step 4: Simplify right side
    1,209.57x = 1,144,513.22
  5. Step 5: Solve for x
    x = 1,144,513.22/1,209.57
  6. Step 6: Final answer
    x = 946.21

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.