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Finding the Fourth Proportional to 665.46, 997.11 and 421.20

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Solution

The fourth proportional to 665.46, 997.11 and 421.20 is: 631.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.46 : 997.11 = 421.20 : x
  2. Step 2: Convert to fraction form
    665.46/997.11 = 421.20/x
  3. Step 3: Cross multiply
    665.46x = 997.11 × 421.20
  4. Step 4: Simplify right side
    665.46x = 419,982.73
  5. Step 5: Solve for x
    x = 419,982.73/665.46
  6. Step 6: Final answer
    x = 631.12

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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.