Finding the Fourth Proportional to 1,398.77, 1,931.21 and 868.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.77 : 1,931.21 = 868.22 : x
2. Step 2: Convert to fraction form
   1,398.77/1,931.21 = 868.22/x
3. Step 3: Cross multiply
   1,398.77x = 1,931.21 × 868.22
4. Step 4: Simplify right side
   1,398.77x = 1,676,715.15
5. Step 5: Solve for x
   x = 1,676,715.15/1,398.77
6. Step 6: Final answer
   x = 1,198.71