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Finding the Fourth Proportional to 80.67, 121.00 and 31.90

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Solution

The fourth proportional to 80.67, 121.00 and 31.90 is: 47.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.67 : 121.00 = 31.90 : x
  2. Step 2: Convert to fraction form
    80.67/121.00 = 31.90/x
  3. Step 3: Cross multiply
    80.67x = 121.00 × 31.90
  4. Step 4: Simplify right side
    80.67x = 3,860.23
  5. Step 5: Solve for x
    x = 3,860.23/80.67
  6. Step 6: Final answer
    x = 47.85

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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.