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Finding the Fourth Proportional to 517.91, 780.37 and 428.61

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Solution

The fourth proportional to 517.91, 780.37 and 428.61 is: 645.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    517.91 : 780.37 = 428.61 : x
  2. Step 2: Convert to fraction form
    517.91/780.37 = 428.61/x
  3. Step 3: Cross multiply
    517.91x = 780.37 × 428.61
  4. Step 4: Simplify right side
    517.91x = 334,474.39
  5. Step 5: Solve for x
    x = 334,474.39/517.91
  6. Step 6: Final answer
    x = 645.82

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.