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Finding the Fourth Proportional to 311.78, 429.88 and 255.56

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Solution

The fourth proportional to 311.78, 429.88 and 255.56 is: 352.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.78 : 429.88 = 255.56 : x
  2. Step 2: Convert to fraction form
    311.78/429.88 = 255.56/x
  3. Step 3: Cross multiply
    311.78x = 429.88 × 255.56
  4. Step 4: Simplify right side
    311.78x = 109,861.94
  5. Step 5: Solve for x
    x = 109,861.94/311.78
  6. Step 6: Final answer
    x = 352.38

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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.