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Finding the Fourth Proportional to 311.96, 430.90 and 309.54

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Solution

The fourth proportional to 311.96, 430.90 and 309.54 is: 427.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.96 : 430.90 = 309.54 : x
  2. Step 2: Convert to fraction form
    311.96/430.90 = 309.54/x
  3. Step 3: Cross multiply
    311.96x = 430.90 × 309.54
  4. Step 4: Simplify right side
    311.96x = 133,380.79
  5. Step 5: Solve for x
    x = 133,380.79/311.96
  6. Step 6: Final answer
    x = 427.56

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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.