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Finding the Fourth Proportional to 83.40, 114.85 and 81.61

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Solution

The fourth proportional to 83.40, 114.85 and 81.61 is: 112.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.40 : 114.85 = 81.61 : x
  2. Step 2: Convert to fraction form
    83.40/114.85 = 81.61/x
  3. Step 3: Cross multiply
    83.40x = 114.85 × 81.61
  4. Step 4: Simplify right side
    83.40x = 9,372.72
  5. Step 5: Solve for x
    x = 9,372.72/83.40
  6. Step 6: Final answer
    x = 112.39

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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.