Finding the Fourth Proportional to 1,131.89, 1,697.41 and 391.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.89 : 1,697.41 = 391.31 : x
2. Step 2: Convert to fraction form
   1,131.89/1,697.41 = 391.31/x
3. Step 3: Cross multiply
   1,131.89x = 1,697.41 × 391.31
4. Step 4: Simplify right side
   1,131.89x = 664,213.51
5. Step 5: Solve for x
   x = 664,213.51/1,131.89
6. Step 6: Final answer
   x = 586.82