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Finding the Fourth Proportional to 311.58, 428.72 and 272.09

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Solution

The fourth proportional to 311.58, 428.72 and 272.09 is: 374.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.58 : 428.72 = 272.09 : x
  2. Step 2: Convert to fraction form
    311.58/428.72 = 272.09/x
  3. Step 3: Cross multiply
    311.58x = 428.72 × 272.09
  4. Step 4: Simplify right side
    311.58x = 116,646.92
  5. Step 5: Solve for x
    x = 116,646.92/311.58
  6. Step 6: Final answer
    x = 374.37

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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.