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Finding the Fourth Proportional to 311.07, 428.53 and 217.65

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Solution

The fourth proportional to 311.07, 428.53 and 217.65 is: 299.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.07 : 428.53 = 217.65 : x
  2. Step 2: Convert to fraction form
    311.07/428.53 = 217.65/x
  3. Step 3: Cross multiply
    311.07x = 428.53 × 217.65
  4. Step 4: Simplify right side
    311.07x = 93,267.96
  5. Step 5: Solve for x
    x = 93,267.96/311.07
  6. Step 6: Final answer
    x = 299.83

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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.