Finding the Fourth Proportional to 2,087.75, 3,131.83 and 771.85

Step by Step Solution

1. Step 1: Write the proportion equation
   2,087.75 : 3,131.83 = 771.85 : x
2. Step 2: Convert to fraction form
   2,087.75/3,131.83 = 771.85/x
3. Step 3: Cross multiply
   2,087.75x = 3,131.83 × 771.85
4. Step 4: Simplify right side
   2,087.75x = 2,417,297.09
5. Step 5: Solve for x
   x = 2,417,297.09/2,087.75
6. Step 6: Final answer
   x = 1,157.85