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Finding the Fourth Proportional to 81.78, 113.00 and 68.47

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Solution

The fourth proportional to 81.78, 113.00 and 68.47 is: 94.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.78 : 113.00 = 68.47 : x
  2. Step 2: Convert to fraction form
    81.78/113.00 = 68.47/x
  3. Step 3: Cross multiply
    81.78x = 113.00 × 68.47
  4. Step 4: Simplify right side
    81.78x = 7,736.49
  5. Step 5: Solve for x
    x = 7,736.49/81.78
  6. Step 6: Final answer
    x = 94.61

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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.