Finding the Fourth Proportional to 128,976.25, 177,987.22 and 72,387.62

Step by Step Solution

1. Step 1: Write the proportion equation
   128,976.25 : 177,987.22 = 72,387.62 : x
2. Step 2: Convert to fraction form
   128,976.25/177,987.22 = 72,387.62/x
3. Step 3: Cross multiply
   128,976.25x = 177,987.22 × 72,387.62
4. Step 4: Simplify right side
   128,976.25x = 12,884,071,510.22
5. Step 5: Solve for x
   x = 12,884,071,510.22/128,976.25
6. Step 6: Final answer
   x = 99,894.92