Finding the Fourth Proportional to 2,087.12, 3,131.60 and 992.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,087.12 : 3,131.60 = 992.28 : x
2. Step 2: Convert to fraction form
   2,087.12/3,131.60 = 992.28/x
3. Step 3: Cross multiply
   2,087.12x = 3,131.60 × 992.28
4. Step 4: Simplify right side
   2,087.12x = 3,107,424.05
5. Step 5: Solve for x
   x = 3,107,424.05/2,087.12
6. Step 6: Final answer
   x = 1,488.86