Finding the Fourth Proportional to 1,222.89, 1,689.82 and 890.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.89 : 1,689.82 = 890.73 : x
2. Step 2: Convert to fraction form
   1,222.89/1,689.82 = 890.73/x
3. Step 3: Cross multiply
   1,222.89x = 1,689.82 × 890.73
4. Step 4: Simplify right side
   1,222.89x = 1,505,173.37
5. Step 5: Solve for x
   x = 1,505,173.37/1,222.89
6. Step 6: Final answer
   x = 1,230.83