Finding the Fourth Proportional to 1,386.10, 1,908.93 and 1,355.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.10 : 1,908.93 = 1,355.86 : x
2. Step 2: Convert to fraction form
   1,386.10/1,908.93 = 1,355.86/x
3. Step 3: Cross multiply
   1,386.10x = 1,908.93 × 1,355.86
4. Step 4: Simplify right side
   1,386.10x = 2,588,241.83
5. Step 5: Solve for x
   x = 2,588,241.83/1,386.10
6. Step 6: Final answer
   x = 1,867.28