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Finding the Fourth Proportional to 521.30, 781.15 and 439.70

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Solution

The fourth proportional to 521.30, 781.15 and 439.70 is: 658.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.30 : 781.15 = 439.70 : x
  2. Step 2: Convert to fraction form
    521.30/781.15 = 439.70/x
  3. Step 3: Cross multiply
    521.30x = 781.15 × 439.70
  4. Step 4: Simplify right side
    521.30x = 343,471.66
  5. Step 5: Solve for x
    x = 343,471.66/521.30
  6. Step 6: Final answer
    x = 658.88

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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.