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Finding the Fourth Proportional to 83.76, 125.40 and 71.61

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Solution

The fourth proportional to 83.76, 125.40 and 71.61 is: 107.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.76 : 125.40 = 71.61 : x
  2. Step 2: Convert to fraction form
    83.76/125.40 = 71.61/x
  3. Step 3: Cross multiply
    83.76x = 125.40 × 71.61
  4. Step 4: Simplify right side
    83.76x = 8,979.89
  5. Step 5: Solve for x
    x = 8,979.89/83.76
  6. Step 6: Final answer
    x = 107.21

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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.