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Finding the Fourth Proportional to 427.14, 640.31 and 138.38

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Solution

The fourth proportional to 427.14, 640.31 and 138.38 is: 207.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.14 : 640.31 = 138.38 : x
  2. Step 2: Convert to fraction form
    427.14/640.31 = 138.38/x
  3. Step 3: Cross multiply
    427.14x = 640.31 × 138.38
  4. Step 4: Simplify right side
    427.14x = 88,602.20
  5. Step 5: Solve for x
    x = 88,602.20/427.14
  6. Step 6: Final answer
    x = 207.43

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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.