Finding the Fourth Proportional to 1,409.40, 1,945.15 and 811.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,409.40 : 1,945.15 = 811.89 : x
2. Step 2: Convert to fraction form
   1,409.40/1,945.15 = 811.89/x
3. Step 3: Cross multiply
   1,409.40x = 1,945.15 × 811.89
4. Step 4: Simplify right side
   1,409.40x = 1,579,245.80
5. Step 5: Solve for x
   x = 1,579,245.80/1,409.40
6. Step 6: Final answer
   x = 1,120.51