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Finding the Fourth Proportional to 84.26, 125.70 and 81.78

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Solution

The fourth proportional to 84.26, 125.70 and 81.78 is: 121.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.26 : 125.70 = 81.78 : x
  2. Step 2: Convert to fraction form
    84.26/125.70 = 81.78/x
  3. Step 3: Cross multiply
    84.26x = 125.70 × 81.78
  4. Step 4: Simplify right side
    84.26x = 10,278.97
  5. Step 5: Solve for x
    x = 10,278.97/84.26
  6. Step 6: Final answer
    x = 121.99

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.