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Finding the Fourth Proportional to 81.61, 112.56 and 72.97

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Solution

The fourth proportional to 81.61, 112.56 and 72.97 is: 100.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.61 : 112.56 = 72.97 : x
  2. Step 2: Convert to fraction form
    81.61/112.56 = 72.97/x
  3. Step 3: Cross multiply
    81.61x = 112.56 × 72.97
  4. Step 4: Simplify right side
    81.61x = 8,212.95
  5. Step 5: Solve for x
    x = 8,212.95/81.61
  6. Step 6: Final answer
    x = 100.64

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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.