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Finding the Fourth Proportional to 80.31, 120.66 and 71.67

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Solution

The fourth proportional to 80.31, 120.66 and 71.67 is: 107.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.31 : 120.66 = 71.67 : x
  2. Step 2: Convert to fraction form
    80.31/120.66 = 71.67/x
  3. Step 3: Cross multiply
    80.31x = 120.66 × 71.67
  4. Step 4: Simplify right side
    80.31x = 8,647.70
  5. Step 5: Solve for x
    x = 8,647.70/80.31
  6. Step 6: Final answer
    x = 107.68

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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.