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Finding the Fourth Proportional to 428.22, 640.74 and 254.98

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Solution

The fourth proportional to 428.22, 640.74 and 254.98 is: 381.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.22 : 640.74 = 254.98 : x
  2. Step 2: Convert to fraction form
    428.22/640.74 = 254.98/x
  3. Step 3: Cross multiply
    428.22x = 640.74 × 254.98
  4. Step 4: Simplify right side
    428.22x = 163,375.49
  5. Step 5: Solve for x
    x = 163,375.49/428.22
  6. Step 6: Final answer
    x = 381.52

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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.