Finding the Fourth Proportional to 2,074.76, 3,111.49 and 687.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,074.76 : 3,111.49 = 687.78 : x
2. Step 2: Convert to fraction form
   2,074.76/3,111.49 = 687.78/x
3. Step 3: Cross multiply
   2,074.76x = 3,111.49 × 687.78
4. Step 4: Simplify right side
   2,074.76x = 2,140,018.87
5. Step 5: Solve for x
   x = 2,140,018.87/2,074.76
6. Step 6: Final answer
   x = 1,031.46