Finding the Fourth Proportional to 2,790.02, 4,182.31 and 1,328.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,790.02 : 4,182.31 = 1,328.78 : x
2. Step 2: Convert to fraction form
   2,790.02/4,182.31 = 1,328.78/x
3. Step 3: Cross multiply
   2,790.02x = 4,182.31 × 1,328.78
4. Step 4: Simplify right side
   2,790.02x = 5,557,369.88
5. Step 5: Solve for x
   x = 5,557,369.88/2,790.02
6. Step 6: Final answer
   x = 1,991.87