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Finding the Fourth Proportional to 638.82, 881.42 and 428.63

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Solution

The fourth proportional to 638.82, 881.42 and 428.63 is: 591.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.82 : 881.42 = 428.63 : x
  2. Step 2: Convert to fraction form
    638.82/881.42 = 428.63/x
  3. Step 3: Cross multiply
    638.82x = 881.42 × 428.63
  4. Step 4: Simplify right side
    638.82x = 377,796.50
  5. Step 5: Solve for x
    x = 377,796.50/638.82
  6. Step 6: Final answer
    x = 591.40

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.