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Finding the Fourth Proportional to 83.20, 123.20 and 81.60

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Solution

The fourth proportional to 83.20, 123.20 and 81.60 is: 120.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.20 : 123.20 = 81.60 : x
  2. Step 2: Convert to fraction form
    83.20/123.20 = 81.60/x
  3. Step 3: Cross multiply
    83.20x = 123.20 × 81.60
  4. Step 4: Simplify right side
    83.20x = 10,053.12
  5. Step 5: Solve for x
    x = 10,053.12/83.20
  6. Step 6: Final answer
    x = 120.83

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Why These Related Problems?

These problems maintain the same ratio (1.48) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.