Finding the Fourth Proportional to 2,381.78, 3,287.06 and 1,387.15

Step by Step Solution

1. Step 1: Write the proportion equation
   2,381.78 : 3,287.06 = 1,387.15 : x
2. Step 2: Convert to fraction form
   2,381.78/3,287.06 = 1,387.15/x
3. Step 3: Cross multiply
   2,381.78x = 3,287.06 × 1,387.15
4. Step 4: Simplify right side
   2,381.78x = 4,559,645.28
5. Step 5: Solve for x
   x = 4,559,645.28/2,381.78
6. Step 6: Final answer
   x = 1,914.39