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Finding the Fourth Proportional to 428.43, 641.78 and 196.99

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Solution

The fourth proportional to 428.43, 641.78 and 196.99 is: 295.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.43 : 641.78 = 196.99 : x
  2. Step 2: Convert to fraction form
    428.43/641.78 = 196.99/x
  3. Step 3: Cross multiply
    428.43x = 641.78 × 196.99
  4. Step 4: Simplify right side
    428.43x = 126,426.65
  5. Step 5: Solve for x
    x = 126,426.65/428.43
  6. Step 6: Final answer
    x = 295.09

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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.