Finding the Fourth Proportional to 1,408.90, 2,111.33 and 791.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,408.90 : 2,111.33 = 791.31 : x
2. Step 2: Convert to fraction form
   1,408.90/2,111.33 = 791.31/x
3. Step 3: Cross multiply
   1,408.90x = 2,111.33 × 791.31
4. Step 4: Simplify right side
   1,408.90x = 1,670,711.59
5. Step 5: Solve for x
   x = 1,670,711.59/1,408.90
6. Step 6: Final answer
   x = 1,185.83