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Finding the Fourth Proportional to 399.31, 551.13 and 281.86

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Solution

The fourth proportional to 399.31, 551.13 and 281.86 is: 389.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.31 : 551.13 = 281.86 : x
  2. Step 2: Convert to fraction form
    399.31/551.13 = 281.86/x
  3. Step 3: Cross multiply
    399.31x = 551.13 × 281.86
  4. Step 4: Simplify right side
    399.31x = 155,341.50
  5. Step 5: Solve for x
    x = 155,341.50/399.31
  6. Step 6: Final answer
    x = 389.02

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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.