Finding the Fourth Proportional to 2,087.31, 3,132.51 and 991.68

Step by Step Solution

1. Step 1: Write the proportion equation
   2,087.31 : 3,132.51 = 991.68 : x
2. Step 2: Convert to fraction form
   2,087.31/3,132.51 = 991.68/x
3. Step 3: Cross multiply
   2,087.31x = 3,132.51 × 991.68
4. Step 4: Simplify right side
   2,087.31x = 3,106,447.52
5. Step 5: Solve for x
   x = 3,106,447.52/2,087.31
6. Step 6: Final answer
   x = 1,488.25