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Finding the Fourth Proportional to 812.56, 1,219 and 422.75

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Solution

The fourth proportional to 812.56, 1,219 and 422.75 is: 634.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.56 : 1,219 = 422.75 : x
  2. Step 2: Convert to fraction form
    812.56/1,219 = 422.75/x
  3. Step 3: Cross multiply
    812.56x = 1,219 × 422.75
  4. Step 4: Simplify right side
    812.56x = 515,332.25
  5. Step 5: Solve for x
    x = 515,332.25/812.56
  6. Step 6: Final answer
    x = 634.21

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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.