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Finding the Fourth Proportional to 521.57, 781.99 and 261.39

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Solution

The fourth proportional to 521.57, 781.99 and 261.39 is: 391.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.57 : 781.99 = 261.39 : x
  2. Step 2: Convert to fraction form
    521.57/781.99 = 261.39/x
  3. Step 3: Cross multiply
    521.57x = 781.99 × 261.39
  4. Step 4: Simplify right side
    521.57x = 204,402.41
  5. Step 5: Solve for x
    x = 204,402.41/521.57
  6. Step 6: Final answer
    x = 391.90

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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.