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Finding the Fourth Proportional to 664.32, 997.31 and 421.86

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Solution

The fourth proportional to 664.32, 997.31 and 421.86 is: 633.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.32 : 997.31 = 421.86 : x
  2. Step 2: Convert to fraction form
    664.32/997.31 = 421.86/x
  3. Step 3: Cross multiply
    664.32x = 997.31 × 421.86
  4. Step 4: Simplify right side
    664.32x = 420,725.20
  5. Step 5: Solve for x
    x = 420,725.20/664.32
  6. Step 6: Final answer
    x = 633.32

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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.