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Finding the Fourth Proportional to 81.90, 112.89 and 68.76

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Solution

The fourth proportional to 81.90, 112.89 and 68.76 is: 94.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.90 : 112.89 = 68.76 : x
  2. Step 2: Convert to fraction form
    81.90/112.89 = 68.76/x
  3. Step 3: Cross multiply
    81.90x = 112.89 × 68.76
  4. Step 4: Simplify right side
    81.90x = 7,761.41
  5. Step 5: Solve for x
    x = 7,761.41/81.90
  6. Step 6: Final answer
    x = 94.77

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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.