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Finding the Fourth Proportional to 426.11, 639.18 and 209.43

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Solution

The fourth proportional to 426.11, 639.18 and 209.43 is: 314.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.11 : 639.18 = 209.43 : x
  2. Step 2: Convert to fraction form
    426.11/639.18 = 209.43/x
  3. Step 3: Cross multiply
    426.11x = 639.18 × 209.43
  4. Step 4: Simplify right side
    426.11x = 133,863.47
  5. Step 5: Solve for x
    x = 133,863.47/426.11
  6. Step 6: Final answer
    x = 314.16

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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.