Finding the Fourth Proportional to 139,012.16, 191,947.20 and 128,397.92

Step by Step Solution

1. Step 1: Write the proportion equation
   139,012.16 : 191,947.20 = 128,397.92 : x
2. Step 2: Convert to fraction form
   139,012.16/191,947.20 = 128,397.92/x
3. Step 3: Cross multiply
   139,012.16x = 191,947.20 × 128,397.92
4. Step 4: Simplify right side
   139,012.16x = 24,645,621,229.82
5. Step 5: Solve for x
   x = 24,645,621,229.82/139,012.16
6. Step 6: Final answer
   x = 177,291.12