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Finding the Fourth Proportional to 311.91, 430.20 and 213.72

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Solution

The fourth proportional to 311.91, 430.20 and 213.72 is: 294.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.91 : 430.20 = 213.72 : x
  2. Step 2: Convert to fraction form
    311.91/430.20 = 213.72/x
  3. Step 3: Cross multiply
    311.91x = 430.20 × 213.72
  4. Step 4: Simplify right side
    311.91x = 91,942.34
  5. Step 5: Solve for x
    x = 91,942.34/311.91
  6. Step 6: Final answer
    x = 294.77

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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.