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Finding the Fourth Proportional to 684.20, 1,025.61 and 391.38

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Solution

The fourth proportional to 684.20, 1,025.61 and 391.38 is: 586.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.20 : 1,025.61 = 391.38 : x
  2. Step 2: Convert to fraction form
    684.20/1,025.61 = 391.38/x
  3. Step 3: Cross multiply
    684.20x = 1,025.61 × 391.38
  4. Step 4: Simplify right side
    684.20x = 401,405.90
  5. Step 5: Solve for x
    x = 401,405.90/684.20
  6. Step 6: Final answer
    x = 586.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.