Finding the Fourth Proportional to 139,128.72, 191,969.64 and 88,161.36

Step by Step Solution

1. Step 1: Write the proportion equation
   139,128.72 : 191,969.64 = 88,161.36 : x
2. Step 2: Convert to fraction form
   139,128.72/191,969.64 = 88,161.36/x
3. Step 3: Cross multiply
   139,128.72x = 191,969.64 × 88,161.36
4. Step 4: Simplify right side
   139,128.72x = 16,924,304,541.11
5. Step 5: Solve for x
   x = 16,924,304,541.11/139,128.72
6. Step 6: Final answer
   x = 121,644.94