Finding the Fourth Proportional to 1,401.20, 1,934.12 and 811.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.20 : 1,934.12 = 811.92 : x
2. Step 2: Convert to fraction form
   1,401.20/1,934.12 = 811.92/x
3. Step 3: Cross multiply
   1,401.20x = 1,934.12 × 811.92
4. Step 4: Simplify right side
   1,401.20x = 1,570,350.71
5. Step 5: Solve for x
   x = 1,570,350.71/1,401.20
6. Step 6: Final answer
   x = 1,120.72