Finding the Fourth Proportional to 1,381.30, 1,906.02 and 783.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.30 : 1,906.02 = 783.78 : x
2. Step 2: Convert to fraction form
   1,381.30/1,906.02 = 783.78/x
3. Step 3: Cross multiply
   1,381.30x = 1,906.02 × 783.78
4. Step 4: Simplify right side
   1,381.30x = 1,493,900.36
5. Step 5: Solve for x
   x = 1,493,900.36/1,381.30
6. Step 6: Final answer
   x = 1,081.52