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Finding the Fourth Proportional to 978.12, 1,349.92 and 558.54

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Solution

The fourth proportional to 978.12, 1,349.92 and 558.54 is: 770.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.12 : 1,349.92 = 558.54 : x
  2. Step 2: Convert to fraction form
    978.12/1,349.92 = 558.54/x
  3. Step 3: Cross multiply
    978.12x = 1,349.92 × 558.54
  4. Step 4: Simplify right side
    978.12x = 753,984.32
  5. Step 5: Solve for x
    x = 753,984.32/978.12
  6. Step 6: Final answer
    x = 770.85

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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.