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Finding the Fourth Proportional to 311.25, 428.68 and 289.73

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Solution

The fourth proportional to 311.25, 428.68 and 289.73 is: 399.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.25 : 428.68 = 289.73 : x
  2. Step 2: Convert to fraction form
    311.25/428.68 = 289.73/x
  3. Step 3: Cross multiply
    311.25x = 428.68 × 289.73
  4. Step 4: Simplify right side
    311.25x = 124,201.46
  5. Step 5: Solve for x
    x = 124,201.46/311.25
  6. Step 6: Final answer
    x = 399.04

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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.