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Finding the Fourth Proportional to 685.87, 946.48 and 391.13

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Solution

The fourth proportional to 685.87, 946.48 and 391.13 is: 539.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.87 : 946.48 = 391.13 : x
  2. Step 2: Convert to fraction form
    685.87/946.48 = 391.13/x
  3. Step 3: Cross multiply
    685.87x = 946.48 × 391.13
  4. Step 4: Simplify right side
    685.87x = 370,195.29
  5. Step 5: Solve for x
    x = 370,195.29/685.87
  6. Step 6: Final answer
    x = 539.75

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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.