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Finding the Fourth Proportional to 681.16, 1,021.90 and 392

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Solution

The fourth proportional to 681.16, 1,021.90 and 392 is: 588.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.16 : 1,021.90 = 392 : x
  2. Step 2: Convert to fraction form
    681.16/1,021.90 = 392/x
  3. Step 3: Cross multiply
    681.16x = 1,021.90 × 392
  4. Step 4: Simplify right side
    681.16x = 400,584.80
  5. Step 5: Solve for x
    x = 400,584.80/681.16
  6. Step 6: Final answer
    x = 588.09

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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.