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Finding the Fourth Proportional to 638.28, 880.91 and 389.60

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Solution

The fourth proportional to 638.28, 880.91 and 389.60 is: 537.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.28 : 880.91 = 389.60 : x
  2. Step 2: Convert to fraction form
    638.28/880.91 = 389.60/x
  3. Step 3: Cross multiply
    638.28x = 880.91 × 389.60
  4. Step 4: Simplify right side
    638.28x = 343,202.54
  5. Step 5: Solve for x
    x = 343,202.54/638.28
  6. Step 6: Final answer
    x = 537.70

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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.