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Finding the Fourth Proportional to 311.76, 428.76 and 272.88

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Solution

The fourth proportional to 311.76, 428.76 and 272.88 is: 375.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.76 : 428.76 = 272.88 : x
  2. Step 2: Convert to fraction form
    311.76/428.76 = 272.88/x
  3. Step 3: Cross multiply
    311.76x = 428.76 × 272.88
  4. Step 4: Simplify right side
    311.76x = 117,000.03
  5. Step 5: Solve for x
    x = 117,000.03/311.76
  6. Step 6: Final answer
    x = 375.29

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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.