Finding the Fourth Proportional to 1,445.10, 1,993.89 and 855.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,445.10 : 1,993.89 = 855.78 : x
2. Step 2: Convert to fraction form
   1,445.10/1,993.89 = 855.78/x
3. Step 3: Cross multiply
   1,445.10x = 1,993.89 × 855.78
4. Step 4: Simplify right side
   1,445.10x = 1,706,331.18
5. Step 5: Solve for x
   x = 1,706,331.18/1,445.10
6. Step 6: Final answer
   x = 1,180.77