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Finding the Fourth Proportional to 426.75, 640.13 and 138.20

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Solution

The fourth proportional to 426.75, 640.13 and 138.20 is: 207.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.75 : 640.13 = 138.20 : x
  2. Step 2: Convert to fraction form
    426.75/640.13 = 138.20/x
  3. Step 3: Cross multiply
    426.75x = 640.13 × 138.20
  4. Step 4: Simplify right side
    426.75x = 88,462.07
  5. Step 5: Solve for x
    x = 88,462.07/426.75
  6. Step 6: Final answer
    x = 207.29

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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.