Finding the Fourth Proportional to 12,799.10, 19,155.30 and 7,871.86

Step by Step Solution

1. Step 1: Write the proportion equation
   12,799.10 : 19,155.30 = 7,871.86 : x
2. Step 2: Convert to fraction form
   12,799.10/19,155.30 = 7,871.86/x
3. Step 3: Cross multiply
   12,799.10x = 19,155.30 × 7,871.86
4. Step 4: Simplify right side
   12,799.10x = 150,787,839.86
5. Step 5: Solve for x
   x = 150,787,839.86/12,799.10
6. Step 6: Final answer
   x = 11,781.13