Finding the Fourth Proportional to 128,686.56, 177,594.72 and 72,116.16

Step by Step Solution

1. Step 1: Write the proportion equation
   128,686.56 : 177,594.72 = 72,116.16 : x
2. Step 2: Convert to fraction form
   128,686.56/177,594.72 = 72,116.16/x
3. Step 3: Cross multiply
   128,686.56x = 177,594.72 × 72,116.16
4. Step 4: Simplify right side
   128,686.56x = 12,807,449,242.68
5. Step 5: Solve for x
   x = 12,807,449,242.68/128,686.56
6. Step 6: Final answer
   x = 99,524.37