Finding the Fourth Proportional to 2,069.78, 3,105.12 and 664.17

Step by Step Solution

1. Step 1: Write the proportion equation
   2,069.78 : 3,105.12 = 664.17 : x
2. Step 2: Convert to fraction form
   2,069.78/3,105.12 = 664.17/x
3. Step 3: Cross multiply
   2,069.78x = 3,105.12 × 664.17
4. Step 4: Simplify right side
   2,069.78x = 2,062,327.55
5. Step 5: Solve for x
   x = 2,062,327.55/2,069.78
6. Step 6: Final answer
   x = 996.40