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Finding the Fourth Proportional to 428.14, 641.94 and 135.55

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Solution

The fourth proportional to 428.14, 641.94 and 135.55 is: 203.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.14 : 641.94 = 135.55 : x
  2. Step 2: Convert to fraction form
    428.14/641.94 = 135.55/x
  3. Step 3: Cross multiply
    428.14x = 641.94 × 135.55
  4. Step 4: Simplify right side
    428.14x = 87,014.97
  5. Step 5: Solve for x
    x = 87,014.97/428.14
  6. Step 6: Final answer
    x = 203.24

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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.