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Finding the Fourth Proportional to 425.72, 638.81 and 209.31

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Solution

The fourth proportional to 425.72, 638.81 and 209.31 is: 314.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.72 : 638.81 = 209.31 : x
  2. Step 2: Convert to fraction form
    425.72/638.81 = 209.31/x
  3. Step 3: Cross multiply
    425.72x = 638.81 × 209.31
  4. Step 4: Simplify right side
    425.72x = 133,709.32
  5. Step 5: Solve for x
    x = 133,709.32/425.72
  6. Step 6: Final answer
    x = 314.08

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.