Finding the Fourth Proportional to 259,626.72, 389,443.20 and 91,151.28

Step by Step Solution

1. Step 1: Write the proportion equation
   259,626.72 : 389,443.20 = 91,151.28 : x
2. Step 2: Convert to fraction form
   259,626.72/389,443.20 = 91,151.28/x
3. Step 3: Cross multiply
   259,626.72x = 389,443.20 × 91,151.28
4. Step 4: Simplify right side
   259,626.72x = 35,498,246,167.30
5. Step 5: Solve for x
   x = 35,498,246,167.30/259,626.72
6. Step 6: Final answer
   x = 136,728.02