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Finding the Fourth Proportional to 138.90, 192.05 and 115.58

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Solution

The fourth proportional to 138.90, 192.05 and 115.58 is: 159.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.90 : 192.05 = 115.58 : x
  2. Step 2: Convert to fraction form
    138.90/192.05 = 115.58/x
  3. Step 3: Cross multiply
    138.90x = 192.05 × 115.58
  4. Step 4: Simplify right side
    138.90x = 22,197.14
  5. Step 5: Solve for x
    x = 22,197.14/138.90
  6. Step 6: Final answer
    x = 159.80

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.