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Finding the Fourth Proportional to 425.99, 638.85 and 209.72

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Solution

The fourth proportional to 425.99, 638.85 and 209.72 is: 314.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.99 : 638.85 = 209.72 : x
  2. Step 2: Convert to fraction form
    425.99/638.85 = 209.72/x
  3. Step 3: Cross multiply
    425.99x = 638.85 × 209.72
  4. Step 4: Simplify right side
    425.99x = 133,979.62
  5. Step 5: Solve for x
    x = 133,979.62/425.99
  6. Step 6: Final answer
    x = 314.51

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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.