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Finding the Fourth Proportional to 638.31, 880.90 and 389.55

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Solution

The fourth proportional to 638.31, 880.90 and 389.55 is: 537.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.31 : 880.90 = 389.55 : x
  2. Step 2: Convert to fraction form
    638.31/880.90 = 389.55/x
  3. Step 3: Cross multiply
    638.31x = 880.90 × 389.55
  4. Step 4: Simplify right side
    638.31x = 343,158.48
  5. Step 5: Solve for x
    x = 343,158.48/638.31
  6. Step 6: Final answer
    x = 537.61

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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.