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Finding the Fourth Proportional to 664.61, 997.99 and 421.61

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Solution

The fourth proportional to 664.61, 997.99 and 421.61 is: 633.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.61 : 997.99 = 421.61 : x
  2. Step 2: Convert to fraction form
    664.61/997.99 = 421.61/x
  3. Step 3: Cross multiply
    664.61x = 997.99 × 421.61
  4. Step 4: Simplify right side
    664.61x = 420,756.52
  5. Step 5: Solve for x
    x = 420,756.52/664.61
  6. Step 6: Final answer
    x = 633.09

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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.