Finding the Fourth Proportional to 2,112.78, 3,164.85 and 1,245

Step by Step Solution

1. Step 1: Write the proportion equation
   2,112.78 : 3,164.85 = 1,245 : x
2. Step 2: Convert to fraction form
   2,112.78/3,164.85 = 1,245/x
3. Step 3: Cross multiply
   2,112.78x = 3,164.85 × 1,245
4. Step 4: Simplify right side
   2,112.78x = 3,940,238.25
5. Step 5: Solve for x
   x = 3,940,238.25/2,112.78
6. Step 6: Final answer
   x = 1,864.95