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Finding the Fourth Proportional to 426.91, 640.36 and 138.35

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Solution

The fourth proportional to 426.91, 640.36 and 138.35 is: 207.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.91 : 640.36 = 138.35 : x
  2. Step 2: Convert to fraction form
    426.91/640.36 = 138.35/x
  3. Step 3: Cross multiply
    426.91x = 640.36 × 138.35
  4. Step 4: Simplify right side
    426.91x = 88,591.86
  5. Step 5: Solve for x
    x = 88,591.86/426.91
  6. Step 6: Final answer
    x = 207.52

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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.