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Finding the Fourth Proportional to 520.78, 781.36 and 315.48

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Solution

The fourth proportional to 520.78, 781.36 and 315.48 is: 473.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.78 : 781.36 = 315.48 : x
  2. Step 2: Convert to fraction form
    520.78/781.36 = 315.48/x
  3. Step 3: Cross multiply
    520.78x = 781.36 × 315.48
  4. Step 4: Simplify right side
    520.78x = 246,503.45
  5. Step 5: Solve for x
    x = 246,503.45/520.78
  6. Step 6: Final answer
    x = 473.34

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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.