Finding the Fourth Proportional to 1,381.12, 1,906 and 791.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.12 : 1,906 = 791.72 : x
2. Step 2: Convert to fraction form
   1,381.12/1,906 = 791.72/x
3. Step 3: Cross multiply
   1,381.12x = 1,906 × 791.72
4. Step 4: Simplify right side
   1,381.12x = 1,509,018.32
5. Step 5: Solve for x
   x = 1,509,018.32/1,381.12
6. Step 6: Final answer
   x = 1,092.60