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Finding the Fourth Proportional to 520.20, 781.38 and 439.20

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Solution

The fourth proportional to 520.20, 781.38 and 439.20 is: 659.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.20 : 781.38 = 439.20 : x
  2. Step 2: Convert to fraction form
    520.20/781.38 = 439.20/x
  3. Step 3: Cross multiply
    520.20x = 781.38 × 439.20
  4. Step 4: Simplify right side
    520.20x = 343,182.10
  5. Step 5: Solve for x
    x = 343,182.10/520.20
  6. Step 6: Final answer
    x = 659.71

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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.