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Finding the Fourth Proportional to 428.38, 640.97 and 255.14

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Solution

The fourth proportional to 428.38, 640.97 and 255.14 is: 381.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.38 : 640.97 = 255.14 : x
  2. Step 2: Convert to fraction form
    428.38/640.97 = 255.14/x
  3. Step 3: Cross multiply
    428.38x = 640.97 × 255.14
  4. Step 4: Simplify right side
    428.38x = 163,537.09
  5. Step 5: Solve for x
    x = 163,537.09/428.38
  6. Step 6: Final answer
    x = 381.76

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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.