Finding the Fourth Proportional to 1,443.23, 1,991.72 and 813.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.23 : 1,991.72 = 813.78 : x
2. Step 2: Convert to fraction form
   1,443.23/1,991.72 = 813.78/x
3. Step 3: Cross multiply
   1,443.23x = 1,991.72 × 813.78
4. Step 4: Simplify right side
   1,443.23x = 1,620,817.83
5. Step 5: Solve for x
   x = 1,620,817.83/1,443.23
6. Step 6: Final answer
   x = 1,123.05