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Finding the Fourth Proportional to 136.42, 188.21 and 81.15

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Solution

The fourth proportional to 136.42, 188.21 and 81.15 is: 111.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.42 : 188.21 = 81.15 : x
  2. Step 2: Convert to fraction form
    136.42/188.21 = 81.15/x
  3. Step 3: Cross multiply
    136.42x = 188.21 × 81.15
  4. Step 4: Simplify right side
    136.42x = 15,273.34
  5. Step 5: Solve for x
    x = 15,273.34/136.42
  6. Step 6: Final answer
    x = 111.96

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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.