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Finding the Fourth Proportional to 81.15, 120.86 and 75.96

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Solution

The fourth proportional to 81.15, 120.86 and 75.96 is: 113.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.15 : 120.86 = 75.96 : x
  2. Step 2: Convert to fraction form
    81.15/120.86 = 75.96/x
  3. Step 3: Cross multiply
    81.15x = 120.86 × 75.96
  4. Step 4: Simplify right side
    81.15x = 9,180.53
  5. Step 5: Solve for x
    x = 9,180.53/81.15
  6. Step 6: Final answer
    x = 113.13

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.