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Finding the Fourth Proportional to 136.39, 188.15 and 81.09

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Solution

The fourth proportional to 136.39, 188.15 and 81.09 is: 111.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.39 : 188.15 = 81.09 : x
  2. Step 2: Convert to fraction form
    136.39/188.15 = 81.09/x
  3. Step 3: Cross multiply
    136.39x = 188.15 × 81.09
  4. Step 4: Simplify right side
    136.39x = 15,257.55
  5. Step 5: Solve for x
    x = 15,257.55/136.39
  6. Step 6: Final answer
    x = 111.87

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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.