Finding the Fourth Proportional to 12,863, 17,738.76 and 8,390.18

Step by Step Solution

1. Step 1: Write the proportion equation
   12,863 : 17,738.76 = 8,390.18 : x
2. Step 2: Convert to fraction form
   12,863/17,738.76 = 8,390.18/x
3. Step 3: Cross multiply
   12,863x = 17,738.76 × 8,390.18
4. Step 4: Simplify right side
   12,863x = 148,831,389.38
5. Step 5: Solve for x
   x = 148,831,389.38/12,863
6. Step 6: Final answer
   x = 11,570.50