Finding the Fourth Proportional to 2,380.78, 3,285.68 and 1,386.15

Step by Step Solution

1. Step 1: Write the proportion equation
   2,380.78 : 3,285.68 = 1,386.15 : x
2. Step 2: Convert to fraction form
   2,380.78/3,285.68 = 1,386.15/x
3. Step 3: Cross multiply
   2,380.78x = 3,285.68 × 1,386.15
4. Step 4: Simplify right side
   2,380.78x = 4,554,445.33
5. Step 5: Solve for x
   x = 4,554,445.33/2,380.78
6. Step 6: Final answer
   x = 1,913.01