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Finding the Fourth Proportional to 92.12, 138.18 and 71.85

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Solution

The fourth proportional to 92.12, 138.18 and 71.85 is: 107.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.12 : 138.18 = 71.85 : x
  2. Step 2: Convert to fraction form
    92.12/138.18 = 71.85/x
  3. Step 3: Cross multiply
    92.12x = 138.18 × 71.85
  4. Step 4: Simplify right side
    92.12x = 9,928.23
  5. Step 5: Solve for x
    x = 9,928.23/92.12
  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.