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Finding the Fourth Proportional to 978.61, 1,351.38 and 629.89

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Solution

The fourth proportional to 978.61, 1,351.38 and 629.89 is: 869.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.61 : 1,351.38 = 629.89 : x
  2. Step 2: Convert to fraction form
    978.61/1,351.38 = 629.89/x
  3. Step 3: Cross multiply
    978.61x = 1,351.38 × 629.89
  4. Step 4: Simplify right side
    978.61x = 851,220.75
  5. Step 5: Solve for x
    x = 851,220.75/978.61
  6. Step 6: Final answer
    x = 869.83

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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.