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Finding the Fourth Proportional to 138.47, 206.82 and 115.38

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Solution

The fourth proportional to 138.47, 206.82 and 115.38 is: 172.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.47 : 206.82 = 115.38 : x
  2. Step 2: Convert to fraction form
    138.47/206.82 = 115.38/x
  3. Step 3: Cross multiply
    138.47x = 206.82 × 115.38
  4. Step 4: Simplify right side
    138.47x = 23,862.89
  5. Step 5: Solve for x
    x = 23,862.89/138.47
  6. Step 6: Final answer
    x = 172.34

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.