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Finding the Fourth Proportional to 681.10, 1,020.30 and 392.20

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Solution

The fourth proportional to 681.10, 1,020.30 and 392.20 is: 587.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.10 : 1,020.30 = 392.20 : x
  2. Step 2: Convert to fraction form
    681.10/1,020.30 = 392.20/x
  3. Step 3: Cross multiply
    681.10x = 1,020.30 × 392.20
  4. Step 4: Simplify right side
    681.10x = 400,161.66
  5. Step 5: Solve for x
    x = 400,161.66/681.10
  6. Step 6: Final answer
    x = 587.52

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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.