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Finding the Fourth Proportional to 311.11, 428.59 and 217.68

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Solution

The fourth proportional to 311.11, 428.59 and 217.68 is: 299.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.11 : 428.59 = 217.68 : x
  2. Step 2: Convert to fraction form
    311.11/428.59 = 217.68/x
  3. Step 3: Cross multiply
    311.11x = 428.59 × 217.68
  4. Step 4: Simplify right side
    311.11x = 93,294.38
  5. Step 5: Solve for x
    x = 93,294.38/311.11
  6. Step 6: Final answer
    x = 299.88

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.