Finding the Fourth Proportional to 1,222.29, 1,686.22 and 780.03

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.29 : 1,686.22 = 780.03 : x
2. Step 2: Convert to fraction form
   1,222.29/1,686.22 = 780.03/x
3. Step 3: Cross multiply
   1,222.29x = 1,686.22 × 780.03
4. Step 4: Simplify right side
   1,222.29x = 1,315,300.24
5. Step 5: Solve for x
   x = 1,315,300.24/1,222.29
6. Step 6: Final answer
   x = 1,076.10