Finding the Fourth Proportional to 1,205.91, 1,806.72 and 839.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,205.91 : 1,806.72 = 839.98 : x
2. Step 2: Convert to fraction form
   1,205.91/1,806.72 = 839.98/x
3. Step 3: Cross multiply
   1,205.91x = 1,806.72 × 839.98
4. Step 4: Simplify right side
   1,205.91x = 1,517,608.67
5. Step 5: Solve for x
   x = 1,517,608.67/1,205.91
6. Step 6: Final answer
   x = 1,258.48