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Finding the Fourth Proportional to 428.87, 642.81 and 197.27

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Solution

The fourth proportional to 428.87, 642.81 and 197.27 is: 295.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.87 : 642.81 = 197.27 : x
  2. Step 2: Convert to fraction form
    428.87/642.81 = 197.27/x
  3. Step 3: Cross multiply
    428.87x = 642.81 × 197.27
  4. Step 4: Simplify right side
    428.87x = 126,809.70
  5. Step 5: Solve for x
    x = 126,809.70/428.87
  6. Step 6: Final answer
    x = 295.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.