Finding the Fourth Proportional to 139,128.38, 191,997.16 and 78,697.72

Step by Step Solution

1. Step 1: Write the proportion equation
   139,128.38 : 191,997.16 = 78,697.72 : x
2. Step 2: Convert to fraction form
   139,128.38/191,997.16 = 78,697.72/x
3. Step 3: Cross multiply
   139,128.38x = 191,997.16 × 78,697.72
4. Step 4: Simplify right side
   139,128.38x = 15,109,738,738.48
5. Step 5: Solve for x
   x = 15,109,738,738.48/139,128.38
6. Step 6: Final answer
   x = 108,602.85