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Finding the Fourth Proportional to 839.20, 1,157.39 and 629.87

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Solution

The fourth proportional to 839.20, 1,157.39 and 629.87 is: 868.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.20 : 1,157.39 = 629.87 : x
  2. Step 2: Convert to fraction form
    839.20/1,157.39 = 629.87/x
  3. Step 3: Cross multiply
    839.20x = 1,157.39 × 629.87
  4. Step 4: Simplify right side
    839.20x = 728,996.30
  5. Step 5: Solve for x
    x = 728,996.30/839.20
  6. Step 6: Final answer
    x = 868.68

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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.