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Finding the Fourth Proportional to 519.78, 717.42 and 312.78

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Solution

The fourth proportional to 519.78, 717.42 and 312.78 is: 431.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    519.78 : 717.42 = 312.78 : x
  2. Step 2: Convert to fraction form
    519.78/717.42 = 312.78/x
  3. Step 3: Cross multiply
    519.78x = 717.42 × 312.78
  4. Step 4: Simplify right side
    519.78x = 224,394.63
  5. Step 5: Solve for x
    x = 224,394.63/519.78
  6. Step 6: Final answer
    x = 431.71

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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.