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Finding the Fourth Proportional to 138.18, 189.60 and 125.85

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Solution

The fourth proportional to 138.18, 189.60 and 125.85 is: 172.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.18 : 189.60 = 125.85 : x
  2. Step 2: Convert to fraction form
    138.18/189.60 = 125.85/x
  3. Step 3: Cross multiply
    138.18x = 189.60 × 125.85
  4. Step 4: Simplify right side
    138.18x = 23,861.16
  5. Step 5: Solve for x
    x = 23,861.16/138.18
  6. Step 6: Final answer
    x = 172.68

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.