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Finding the Fourth Proportional to 683.88, 1,024.85 and 390.78

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Solution

The fourth proportional to 683.88, 1,024.85 and 390.78 is: 585.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    683.88 : 1,024.85 = 390.78 : x
  2. Step 2: Convert to fraction form
    683.88/1,024.85 = 390.78/x
  3. Step 3: Cross multiply
    683.88x = 1,024.85 × 390.78
  4. Step 4: Simplify right side
    683.88x = 400,491.86
  5. Step 5: Solve for x
    x = 400,491.86/683.88
  6. Step 6: Final answer
    x = 585.62

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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.