Finding the Fourth Proportional to 1,443.08, 1,991.37 and 813.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.08 : 1,991.37 = 813.71 : x
2. Step 2: Convert to fraction form
   1,443.08/1,991.37 = 813.71/x
3. Step 3: Cross multiply
   1,443.08x = 1,991.37 × 813.71
4. Step 4: Simplify right side
   1,443.08x = 1,620,397.68
5. Step 5: Solve for x
   x = 1,620,397.68/1,443.08
6. Step 6: Final answer
   x = 1,122.87