Finding the Fourth Proportional to 1,381.05, 1,906.22 and 856.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.05 : 1,906.22 = 856.79 : x
2. Step 2: Convert to fraction form
   1,381.05/1,906.22 = 856.79/x
3. Step 3: Cross multiply
   1,381.05x = 1,906.22 × 856.79
4. Step 4: Simplify right side
   1,381.05x = 1,633,230.23
5. Step 5: Solve for x
   x = 1,633,230.23/1,381.05
6. Step 6: Final answer
   x = 1,182.60