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Finding the Fourth Proportional to 83.10, 124.65 and 81.90

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Solution

The fourth proportional to 83.10, 124.65 and 81.90 is: 122.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.10 : 124.65 = 81.90 : x
  2. Step 2: Convert to fraction form
    83.10/124.65 = 81.90/x
  3. Step 3: Cross multiply
    83.10x = 124.65 × 81.90
  4. Step 4: Simplify right side
    83.10x = 10,208.84
  5. Step 5: Solve for x
    x = 10,208.84/83.10
  6. Step 6: Final answer
    x = 122.85

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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.