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Finding the Fourth Proportional to 426.88, 640.41 and 138.34

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Solution

The fourth proportional to 426.88, 640.41 and 138.34 is: 207.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.88 : 640.41 = 138.34 : x
  2. Step 2: Convert to fraction form
    426.88/640.41 = 138.34/x
  3. Step 3: Cross multiply
    426.88x = 640.41 × 138.34
  4. Step 4: Simplify right side
    426.88x = 88,590.43
  5. Step 5: Solve for x
    x = 88,590.43/426.88
  6. Step 6: Final answer
    x = 207.53

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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.