Finding the Fourth Proportional to 2,630.78, 3,947.92 and 1,091.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,630.78 : 3,947.92 = 1,091.78 : x
2. Step 2: Convert to fraction form
   2,630.78/3,947.92 = 1,091.78/x
3. Step 3: Cross multiply
   2,630.78x = 3,947.92 × 1,091.78
4. Step 4: Simplify right side
   2,630.78x = 4,310,260.10
5. Step 5: Solve for x
   x = 4,310,260.10/2,630.78
6. Step 6: Final answer
   x = 1,638.40