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Finding the Fourth Proportional to 136.85, 205.11 and 71.91

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Solution

The fourth proportional to 136.85, 205.11 and 71.91 is: 107.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.85 : 205.11 = 71.91 : x
  2. Step 2: Convert to fraction form
    136.85/205.11 = 71.91/x
  3. Step 3: Cross multiply
    136.85x = 205.11 × 71.91
  4. Step 4: Simplify right side
    136.85x = 14,749.46
  5. Step 5: Solve for x
    x = 14,749.46/136.85
  6. Step 6: Final answer
    x = 107.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.