Finding the Fourth Proportional to 1,022.96, 1,411.71 and 557.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,022.96 : 1,411.71 = 557.21 : x
2. Step 2: Convert to fraction form
   1,022.96/1,411.71 = 557.21/x
3. Step 3: Cross multiply
   1,022.96x = 1,411.71 × 557.21
4. Step 4: Simplify right side
   1,022.96x = 786,611.87
5. Step 5: Solve for x
   x = 786,611.87/1,022.96
6. Step 6: Final answer
   x = 768.96