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Finding the Fourth Proportional to 684.64, 1,025.87 and 391.60

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Solution

The fourth proportional to 684.64, 1,025.87 and 391.60 is: 586.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    684.64 : 1,025.87 = 391.60 : x
  2. Step 2: Convert to fraction form
    684.64/1,025.87 = 391.60/x
  3. Step 3: Cross multiply
    684.64x = 1,025.87 × 391.60
  4. Step 4: Simplify right side
    684.64x = 401,730.69
  5. Step 5: Solve for x
    x = 401,730.69/684.64
  6. Step 6: Final answer
    x = 586.78

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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.