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Finding the Fourth Proportional to 638.87, 958.31 and 422.40

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Solution

The fourth proportional to 638.87, 958.31 and 422.40 is: 633.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.87 : 958.31 = 422.40 : x
  2. Step 2: Convert to fraction form
    638.87/958.31 = 422.40/x
  3. Step 3: Cross multiply
    638.87x = 958.31 × 422.40
  4. Step 4: Simplify right side
    638.87x = 404,788.03
  5. Step 5: Solve for x
    x = 404,788.03/638.87
  6. Step 6: Final answer
    x = 633.60

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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.