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Finding the Fourth Proportional to 80.85, 121.17 and 66.43

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Solution

The fourth proportional to 80.85, 121.17 and 66.43 is: 99.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.85 : 121.17 = 66.43 : x
  2. Step 2: Convert to fraction form
    80.85/121.17 = 66.43/x
  3. Step 3: Cross multiply
    80.85x = 121.17 × 66.43
  4. Step 4: Simplify right side
    80.85x = 8,049.32
  5. Step 5: Solve for x
    x = 8,049.32/80.85
  6. Step 6: Final answer
    x = 99.56

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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.