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Finding the Fourth Proportional to 83.21, 124.86 and 39.87

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Solution

The fourth proportional to 83.21, 124.86 and 39.87 is: 59.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.21 : 124.86 = 39.87 : x
  2. Step 2: Convert to fraction form
    83.21/124.86 = 39.87/x
  3. Step 3: Cross multiply
    83.21x = 124.86 × 39.87
  4. Step 4: Simplify right side
    83.21x = 4,978.22
  5. Step 5: Solve for x
    x = 4,978.22/83.21
  6. Step 6: Final answer
    x = 59.83

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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.