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Finding the Fourth Proportional to 685.87, 946.49 and 391.08

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Solution

The fourth proportional to 685.87, 946.49 and 391.08 is: 539.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.87 : 946.49 = 391.08 : x
  2. Step 2: Convert to fraction form
    685.87/946.49 = 391.08/x
  3. Step 3: Cross multiply
    685.87x = 946.49 × 391.08
  4. Step 4: Simplify right side
    685.87x = 370,149.58
  5. Step 5: Solve for x
    x = 370,149.58/685.87
  6. Step 6: Final answer
    x = 539.68

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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.