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Finding the Fourth Proportional to 428.63, 639.77 and 418.27

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Solution

The fourth proportional to 428.63, 639.77 and 418.27 is: 624.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.63 : 639.77 = 418.27 : x
  2. Step 2: Convert to fraction form
    428.63/639.77 = 418.27/x
  3. Step 3: Cross multiply
    428.63x = 639.77 × 418.27
  4. Step 4: Simplify right side
    428.63x = 267,592.91
  5. Step 5: Solve for x
    x = 267,592.91/428.63
  6. Step 6: Final answer
    x = 624.31

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.