Finding the Fourth Proportional to 2,057.78, 3,085.40 and 758.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,057.78 : 3,085.40 = 758.90 : x
2. Step 2: Convert to fraction form
   2,057.78/3,085.40 = 758.90/x
3. Step 3: Cross multiply
   2,057.78x = 3,085.40 × 758.90
4. Step 4: Simplify right side
   2,057.78x = 2,341,510.06
5. Step 5: Solve for x
   x = 2,341,510.06/2,057.78
6. Step 6: Final answer
   x = 1,137.88