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Finding the Fourth Proportional to 681.55, 1,021.09 and 388.69

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Solution

The fourth proportional to 681.55, 1,021.09 and 388.69 is: 582.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.55 : 1,021.09 = 388.69 : x
  2. Step 2: Convert to fraction form
    681.55/1,021.09 = 388.69/x
  3. Step 3: Cross multiply
    681.55x = 1,021.09 × 388.69
  4. Step 4: Simplify right side
    681.55x = 396,887.47
  5. Step 5: Solve for x
    x = 396,887.47/681.55
  6. Step 6: Final answer
    x = 582.33

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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.