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Finding the Fourth Proportional to 81.78, 113.01 and 67.02

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Solution

The fourth proportional to 81.78, 113.01 and 67.02 is: 92.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.78 : 113.01 = 67.02 : x
  2. Step 2: Convert to fraction form
    81.78/113.01 = 67.02/x
  3. Step 3: Cross multiply
    81.78x = 113.01 × 67.02
  4. Step 4: Simplify right side
    81.78x = 7,573.93
  5. Step 5: Solve for x
    x = 7,573.93/81.78
  6. Step 6: Final answer
    x = 92.61

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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.