Finding the Fourth Proportional to 1,442.91, 1,991.31 and 813.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,442.91 : 1,991.31 = 813.50 : x
2. Step 2: Convert to fraction form
   1,442.91/1,991.31 = 813.50/x
3. Step 3: Cross multiply
   1,442.91x = 1,991.31 × 813.50
4. Step 4: Simplify right side
   1,442.91x = 1,619,920.73
5. Step 5: Solve for x
   x = 1,619,920.73/1,442.91
6. Step 6: Final answer
   x = 1,122.68