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Finding the Fourth Proportional to 1,209.50, 1,669.11 and 685.70

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Solution

The fourth proportional to 1,209.50, 1,669.11 and 685.70 is: 946.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.50 : 1,669.11 = 685.70 : x
  2. Step 2: Convert to fraction form
    1,209.50/1,669.11 = 685.70/x
  3. Step 3: Cross multiply
    1,209.50x = 1,669.11 × 685.70
  4. Step 4: Simplify right side
    1,209.50x = 1,144,508.73
  5. Step 5: Solve for x
    x = 1,144,508.73/1,209.50
  6. Step 6: Final answer
    x = 946.27

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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.