Finding the Fourth Proportional to 1,531.78, 2,113.83 and 868.64

Step by Step Solution

1. Step 1: Write the proportion equation
   1,531.78 : 2,113.83 = 868.64 : x
2. Step 2: Convert to fraction form
   1,531.78/2,113.83 = 868.64/x
3. Step 3: Cross multiply
   1,531.78x = 2,113.83 × 868.64
4. Step 4: Simplify right side
   1,531.78x = 1,836,146.72
5. Step 5: Solve for x
   x = 1,836,146.72/1,531.78
6. Step 6: Final answer
   x = 1,198.70