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Finding the Fourth Proportional to 665.38, 998.79 and 422.11

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Solution

The fourth proportional to 665.38, 998.79 and 422.11 is: 633.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.38 : 998.79 = 422.11 : x
  2. Step 2: Convert to fraction form
    665.38/998.79 = 422.11/x
  3. Step 3: Cross multiply
    665.38x = 998.79 × 422.11
  4. Step 4: Simplify right side
    665.38x = 421,599.25
  5. Step 5: Solve for x
    x = 421,599.25/665.38
  6. Step 6: Final answer
    x = 633.62

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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.