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Finding the Fourth Proportional to 519.86, 780.21 and 285.66

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Solution

The fourth proportional to 519.86, 780.21 and 285.66 is: 428.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    519.86 : 780.21 = 285.66 : x
  2. Step 2: Convert to fraction form
    519.86/780.21 = 285.66/x
  3. Step 3: Cross multiply
    519.86x = 780.21 × 285.66
  4. Step 4: Simplify right side
    519.86x = 222,874.79
  5. Step 5: Solve for x
    x = 222,874.79/519.86
  6. Step 6: Final answer
    x = 428.72

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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.