Finding the Fourth Proportional to 90,728.79, 136,078.61 and 28,399.29

Step by Step Solution

1. Step 1: Write the proportion equation
   90,728.79 : 136,078.61 = 28,399.29 : x
2. Step 2: Convert to fraction form
   90,728.79/136,078.61 = 28,399.29/x
3. Step 3: Cross multiply
   90,728.79x = 136,078.61 × 28,399.29
4. Step 4: Simplify right side
   90,728.79x = 3,864,535,766.19
5. Step 5: Solve for x
   x = 3,864,535,766.19/90,728.79
6. Step 6: Final answer
   x = 42,594.37