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Finding the Fourth Proportional to 518.50, 781.32 and 429.20

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Solution

The fourth proportional to 518.50, 781.32 and 429.20 is: 646.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.50 : 781.32 = 429.20 : x
  2. Step 2: Convert to fraction form
    518.50/781.32 = 429.20/x
  3. Step 3: Cross multiply
    518.50x = 781.32 × 429.20
  4. Step 4: Simplify right side
    518.50x = 335,342.54
  5. Step 5: Solve for x
    x = 335,342.54/518.50
  6. Step 6: Final answer
    x = 646.76

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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.