Finding the Fourth Proportional to 1,381.91, 1,906.31 and 857.03

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.91 : 1,906.31 = 857.03 : x
2. Step 2: Convert to fraction form
   1,381.91/1,906.31 = 857.03/x
3. Step 3: Cross multiply
   1,381.91x = 1,906.31 × 857.03
4. Step 4: Simplify right side
   1,381.91x = 1,633,755.81
5. Step 5: Solve for x
   x = 1,633,755.81/1,381.91
6. Step 6: Final answer
   x = 1,182.25