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Finding the Fourth Proportional to 681.96, 1,021.31 and 421.26

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Solution

The fourth proportional to 681.96, 1,021.31 and 421.26 is: 630.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.96 : 1,021.31 = 421.26 : x
  2. Step 2: Convert to fraction form
    681.96/1,021.31 = 421.26/x
  3. Step 3: Cross multiply
    681.96x = 1,021.31 × 421.26
  4. Step 4: Simplify right side
    681.96x = 430,237.05
  5. Step 5: Solve for x
    x = 430,237.05/681.96
  6. Step 6: Final answer
    x = 630.88

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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.