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Finding the Fourth Proportional to 638.76, 881.14 and 428.70

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Solution

The fourth proportional to 638.76, 881.14 and 428.70 is: 591.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.76 : 881.14 = 428.70 : x
  2. Step 2: Convert to fraction form
    638.76/881.14 = 428.70/x
  3. Step 3: Cross multiply
    638.76x = 881.14 × 428.70
  4. Step 4: Simplify right side
    638.76x = 377,744.72
  5. Step 5: Solve for x
    x = 377,744.72/638.76
  6. Step 6: Final answer
    x = 591.37

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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.