Finding the Fourth Proportional to 1,442.91, 1,991.06 and 813.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,442.91 : 1,991.06 = 813.47 : x
2. Step 2: Convert to fraction form
   1,442.91/1,991.06 = 813.47/x
3. Step 3: Cross multiply
   1,442.91x = 1,991.06 × 813.47
4. Step 4: Simplify right side
   1,442.91x = 1,619,667.58
5. Step 5: Solve for x
   x = 1,619,667.58/1,442.91
6. Step 6: Final answer
   x = 1,122.50