Finding the Fourth Proportional to 1,443.17, 1,991.49 and 813.70

Step by Step Solution

1. Step 1: Write the proportion equation
   1,443.17 : 1,991.49 = 813.70 : x
2. Step 2: Convert to fraction form
   1,443.17/1,991.49 = 813.70/x
3. Step 3: Cross multiply
   1,443.17x = 1,991.49 × 813.70
4. Step 4: Simplify right side
   1,443.17x = 1,620,470.51
5. Step 5: Solve for x
   x = 1,620,470.51/1,443.17
6. Step 6: Final answer
   x = 1,122.86