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Finding the Fourth Proportional to 427.11, 640.54 and 138.48

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Solution

The fourth proportional to 427.11, 640.54 and 138.48 is: 207.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.11 : 640.54 = 138.48 : x
  2. Step 2: Convert to fraction form
    427.11/640.54 = 138.48/x
  3. Step 3: Cross multiply
    427.11x = 640.54 × 138.48
  4. Step 4: Simplify right side
    427.11x = 88,701.98
  5. Step 5: Solve for x
    x = 88,701.98/427.11
  6. Step 6: Final answer
    x = 207.68

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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.