Finding the Fourth Proportional to 1,558.41, 2,335.84 and 680.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,558.41 : 2,335.84 = 680.78 : x
2. Step 2: Convert to fraction form
   1,558.41/2,335.84 = 680.78/x
3. Step 3: Cross multiply
   1,558.41x = 2,335.84 × 680.78
4. Step 4: Simplify right side
   1,558.41x = 1,590,190.72
5. Step 5: Solve for x
   x = 1,590,190.72/1,558.41
6. Step 6: Final answer
   x = 1,020.39