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Finding the Fourth Proportional to 681.57, 1,021.32 and 388.71

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Solution

The fourth proportional to 681.57, 1,021.32 and 388.71 is: 582.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.57 : 1,021.32 = 388.71 : x
  2. Step 2: Convert to fraction form
    681.57/1,021.32 = 388.71/x
  3. Step 3: Cross multiply
    681.57x = 1,021.32 × 388.71
  4. Step 4: Simplify right side
    681.57x = 396,997.30
  5. Step 5: Solve for x
    x = 396,997.30/681.57
  6. Step 6: Final answer
    x = 582.47

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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.