Finding the Fourth Proportional to 2,778.60, 4,165.18 and 1,389.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,778.60 : 4,165.18 = 1,389.86 : x
2. Step 2: Convert to fraction form
   2,778.60/4,165.18 = 1,389.86/x
3. Step 3: Cross multiply
   2,778.60x = 4,165.18 × 1,389.86
4. Step 4: Simplify right side
   2,778.60x = 5,789,017.07
5. Step 5: Solve for x
   x = 5,789,017.07/2,778.60
6. Step 6: Final answer
   x = 2,083.43