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Finding the Fourth Proportional to 681.86, 1,022.78 and 389.20

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Solution

The fourth proportional to 681.86, 1,022.78 and 389.20 is: 583.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.86 : 1,022.78 = 389.20 : x
  2. Step 2: Convert to fraction form
    681.86/1,022.78 = 389.20/x
  3. Step 3: Cross multiply
    681.86x = 1,022.78 × 389.20
  4. Step 4: Simplify right side
    681.86x = 398,065.98
  5. Step 5: Solve for x
    x = 398,065.98/681.86
  6. Step 6: Final answer
    x = 583.79

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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.