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Finding the Fourth Proportional to 426.96, 640.40 and 138.38

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Solution

The fourth proportional to 426.96, 640.40 and 138.38 is: 207.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.96 : 640.40 = 138.38 : x
  2. Step 2: Convert to fraction form
    426.96/640.40 = 138.38/x
  3. Step 3: Cross multiply
    426.96x = 640.40 × 138.38
  4. Step 4: Simplify right side
    426.96x = 88,614.66
  5. Step 5: Solve for x
    x = 88,614.66/426.96
  6. Step 6: Final answer
    x = 207.55

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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.