Finding the Fourth Proportional to 1,222.44, 1,687.88 and 1,002.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.44 : 1,687.88 = 1,002.12 : x
2. Step 2: Convert to fraction form
   1,222.44/1,687.88 = 1,002.12/x
3. Step 3: Cross multiply
   1,222.44x = 1,687.88 × 1,002.12
4. Step 4: Simplify right side
   1,222.44x = 1,691,458.31
5. Step 5: Solve for x
   x = 1,691,458.31/1,222.44
6. Step 6: Final answer
   x = 1,383.67