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Finding the Fourth Proportional to 428.05, 641.78 and 196.62

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Solution

The fourth proportional to 428.05, 641.78 and 196.62 is: 294.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.05 : 641.78 = 196.62 : x
  2. Step 2: Convert to fraction form
    428.05/641.78 = 196.62/x
  3. Step 3: Cross multiply
    428.05x = 641.78 × 196.62
  4. Step 4: Simplify right side
    428.05x = 126,185.80
  5. Step 5: Solve for x
    x = 126,185.80/428.05
  6. Step 6: Final answer
    x = 294.79

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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.