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Finding the Fourth Proportional to 311.89, 467.86 and 80.78

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Solution

The fourth proportional to 311.89, 467.86 and 80.78 is: 121.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.89 : 467.86 = 80.78 : x
  2. Step 2: Convert to fraction form
    311.89/467.86 = 80.78/x
  3. Step 3: Cross multiply
    311.89x = 467.86 × 80.78
  4. Step 4: Simplify right side
    311.89x = 37,791.19
  5. Step 5: Solve for x
    x = 37,791.19/311.89
  6. Step 6: Final answer
    x = 121.17

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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.