Finding the Fourth Proportional to 1,222.57, 1,687.15 and 663.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.57 : 1,687.15 = 663.04 : x
2. Step 2: Convert to fraction form
   1,222.57/1,687.15 = 663.04/x
3. Step 3: Cross multiply
   1,222.57x = 1,687.15 × 663.04
4. Step 4: Simplify right side
   1,222.57x = 1,118,647.94
5. Step 5: Solve for x
   x = 1,118,647.94/1,222.57
6. Step 6: Final answer
   x = 915.00