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Finding the Fourth Proportional to 81.43, 112.14 and 81.18

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Solution

The fourth proportional to 81.43, 112.14 and 81.18 is: 111.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.43 : 112.14 = 81.18 : x
  2. Step 2: Convert to fraction form
    81.43/112.14 = 81.18/x
  3. Step 3: Cross multiply
    81.43x = 112.14 × 81.18
  4. Step 4: Simplify right side
    81.43x = 9,103.73
  5. Step 5: Solve for x
    x = 9,103.73/81.43
  6. Step 6: Final answer
    x = 111.80

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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.