Finding the Fourth Proportional to 139,402.68, 192,369.43 and 78,972.09

Step by Step Solution

1. Step 1: Write the proportion equation
   139,402.68 : 192,369.43 = 78,972.09 : x
2. Step 2: Convert to fraction form
   139,402.68/192,369.43 = 78,972.09/x
3. Step 3: Cross multiply
   139,402.68x = 192,369.43 × 78,972.09
4. Step 4: Simplify right side
   139,402.68x = 15,191,815,544.35
5. Step 5: Solve for x
   x = 15,191,815,544.35/139,402.68
6. Step 6: Final answer
   x = 108,977.93