Finding the Fourth Proportional to 1,443.09, 1,991.44 and 813.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.09 : 1,991.44 = 813.62 : x
2. Step 2: Convert to fraction form
   1,443.09/1,991.44 = 813.62/x
3. Step 3: Cross multiply
   1,443.09x = 1,991.44 × 813.62
4. Step 4: Simplify right side
   1,443.09x = 1,620,273.38
5. Step 5: Solve for x
   x = 1,620,273.38/1,443.09
6. Step 6: Final answer
   x = 1,122.78