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Finding the Fourth Proportional to 81.19, 122.42 and 71.17

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Solution

The fourth proportional to 81.19, 122.42 and 71.17 is: 107.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.19 : 122.42 = 71.17 : x
  2. Step 2: Convert to fraction form
    81.19/122.42 = 71.17/x
  3. Step 3: Cross multiply
    81.19x = 122.42 × 71.17
  4. Step 4: Simplify right side
    81.19x = 8,712.63
  5. Step 5: Solve for x
    x = 8,712.63/81.19
  6. Step 6: Final answer
    x = 107.31

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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.