Finding the Fourth Proportional to 12,981.57, 17,915.90 and 7,949.12

Step by Step Solution

1. Step 1: Write the proportion equation
   12,981.57 : 17,915.90 = 7,949.12 : x
2. Step 2: Convert to fraction form
   12,981.57/17,915.90 = 7,949.12/x
3. Step 3: Cross multiply
   12,981.57x = 17,915.90 × 7,949.12
4. Step 4: Simplify right side
   12,981.57x = 142,415,509.68
5. Step 5: Solve for x
   x = 142,415,509.68/12,981.57
6. Step 6: Final answer
   x = 10,970.59