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Finding the Fourth Proportional to 681.10, 1,021.64 and 421.16

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Solution

The fourth proportional to 681.10, 1,021.64 and 421.16 is: 631.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.10 : 1,021.64 = 421.16 : x
  2. Step 2: Convert to fraction form
    681.10/1,021.64 = 421.16/x
  3. Step 3: Cross multiply
    681.10x = 1,021.64 × 421.16
  4. Step 4: Simplify right side
    681.10x = 430,273.90
  5. Step 5: Solve for x
    x = 430,273.90/681.10
  6. Step 6: Final answer
    x = 631.73

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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.