Finding the Fourth Proportional to 128,735.98, 177,645.86 and 72,136.42

Step by Step Solution

1. Step 1: Write the proportion equation
   128,735.98 : 177,645.86 = 72,136.42 : x
2. Step 2: Convert to fraction form
   128,735.98/177,645.86 = 72,136.42/x
3. Step 3: Cross multiply
   128,735.98x = 177,645.86 × 72,136.42
4. Step 4: Simplify right side
   128,735.98x = 12,814,736,007.54
5. Step 5: Solve for x
   x = 12,814,736,007.54/128,735.98
6. Step 6: Final answer
   x = 99,542.77