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Finding the Fourth Proportional to 81.59, 122.87 and 72.08

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Solution

The fourth proportional to 81.59, 122.87 and 72.08 is: 108.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.59 : 122.87 = 72.08 : x
  2. Step 2: Convert to fraction form
    81.59/122.87 = 72.08/x
  3. Step 3: Cross multiply
    81.59x = 122.87 × 72.08
  4. Step 4: Simplify right side
    81.59x = 8,855.86
  5. Step 5: Solve for x
    x = 8,855.86/81.59
  6. Step 6: Final answer
    x = 108.55

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.