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Finding the Fourth Proportional to 812.88, 1,219.61 and 422.87

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Solution

The fourth proportional to 812.88, 1,219.61 and 422.87 is: 634.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.88 : 1,219.61 = 422.87 : x
  2. Step 2: Convert to fraction form
    812.88/1,219.61 = 422.87/x
  3. Step 3: Cross multiply
    812.88x = 1,219.61 × 422.87
  4. Step 4: Simplify right side
    812.88x = 515,728.27
  5. Step 5: Solve for x
    x = 515,728.27/812.88
  6. Step 6: Final answer
    x = 634.45

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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.