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Finding the Fourth Proportional to 958.78, 1,438.20 and 381.70

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Solution

The fourth proportional to 958.78, 1,438.20 and 381.70 is: 572.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    958.78 : 1,438.20 = 381.70 : x
  2. Step 2: Convert to fraction form
    958.78/1,438.20 = 381.70/x
  3. Step 3: Cross multiply
    958.78x = 1,438.20 × 381.70
  4. Step 4: Simplify right side
    958.78x = 548,960.94
  5. Step 5: Solve for x
    x = 548,960.94/958.78
  6. Step 6: Final answer
    x = 572.56

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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.