Finding the Fourth Proportional to 1,381.40, 1,906.53 and 821.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.40 : 1,906.53 = 821.92 : x
2. Step 2: Convert to fraction form
   1,381.40/1,906.53 = 821.92/x
3. Step 3: Cross multiply
   1,381.40x = 1,906.53 × 821.92
4. Step 4: Simplify right side
   1,381.40x = 1,567,016.84
5. Step 5: Solve for x
   x = 1,567,016.84/1,381.40
6. Step 6: Final answer
   x = 1,134.37