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Finding the Fourth Proportional to 83.21, 124.79 and 31.85

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Solution

The fourth proportional to 83.21, 124.79 and 31.85 is: 47.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.21 : 124.79 = 31.85 : x
  2. Step 2: Convert to fraction form
    83.21/124.79 = 31.85/x
  3. Step 3: Cross multiply
    83.21x = 124.79 × 31.85
  4. Step 4: Simplify right side
    83.21x = 3,973.78
  5. Step 5: Solve for x
    x = 3,973.78/83.21
  6. Step 6: Final answer
    x = 47.76

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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.