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Finding the Fourth Proportional to 638.39, 880.90 and 389.79

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Solution

The fourth proportional to 638.39, 880.90 and 389.79 is: 537.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.39 : 880.90 = 389.79 : x
  2. Step 2: Convert to fraction form
    638.39/880.90 = 389.79/x
  3. Step 3: Cross multiply
    638.39x = 880.90 × 389.79
  4. Step 4: Simplify right side
    638.39x = 343,365.04
  5. Step 5: Solve for x
    x = 343,365.04/638.39
  6. Step 6: Final answer
    x = 537.86

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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.