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Finding the Fourth Proportional to 665.90, 998.85 and 422.70

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Solution

The fourth proportional to 665.90, 998.85 and 422.70 is: 634.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.90 : 998.85 = 422.70 : x
  2. Step 2: Convert to fraction form
    665.90/998.85 = 422.70/x
  3. Step 3: Cross multiply
    665.90x = 998.85 × 422.70
  4. Step 4: Simplify right side
    665.90x = 422,213.90
  5. Step 5: Solve for x
    x = 422,213.90/665.90
  6. Step 6: Final answer
    x = 634.05

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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.