Finding the Fourth Proportional to 1,222.16, 1,830.76 and 789.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.16 : 1,830.76 = 789.60 : x
2. Step 2: Convert to fraction form
   1,222.16/1,830.76 = 789.60/x
3. Step 3: Cross multiply
   1,222.16x = 1,830.76 × 789.60
4. Step 4: Simplify right side
   1,222.16x = 1,445,568.10
5. Step 5: Solve for x
   x = 1,445,568.10/1,222.16
6. Step 6: Final answer
   x = 1,182.80