Finding the Fourth Proportional to 11,981.78, 17,950.76 and 8,686.70

Step by Step Solution

1. Step 1: Write the proportion equation
   11,981.78 : 17,950.76 = 8,686.70 : x
2. Step 2: Convert to fraction form
   11,981.78/17,950.76 = 8,686.70/x
3. Step 3: Cross multiply
   11,981.78x = 17,950.76 × 8,686.70
4. Step 4: Simplify right side
   11,981.78x = 155,932,866.89
5. Step 5: Solve for x
   x = 155,932,866.89/11,981.78
6. Step 6: Final answer
   x = 13,014.17