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Finding the Fourth Proportional to 426.90, 640.36 and 138.36

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Solution

The fourth proportional to 426.90, 640.36 and 138.36 is: 207.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.90 : 640.36 = 138.36 : x
  2. Step 2: Convert to fraction form
    426.90/640.36 = 138.36/x
  3. Step 3: Cross multiply
    426.90x = 640.36 × 138.36
  4. Step 4: Simplify right side
    426.90x = 88,600.21
  5. Step 5: Solve for x
    x = 88,600.21/426.90
  6. Step 6: Final answer
    x = 207.54

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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.