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Finding the Fourth Proportional to 83.81, 125.55 and 81.38

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Solution

The fourth proportional to 83.81, 125.55 and 81.38 is: 121.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.81 : 125.55 = 81.38 : x
  2. Step 2: Convert to fraction form
    83.81/125.55 = 81.38/x
  3. Step 3: Cross multiply
    83.81x = 125.55 × 81.38
  4. Step 4: Simplify right side
    83.81x = 10,216.63
  5. Step 5: Solve for x
    x = 10,216.63/83.81
  6. Step 6: Final answer
    x = 121.91

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.