Finding the Fourth Proportional to 139,921.61, 209,913.60 and 51,173.15

Step by Step Solution

1. Step 1: Write the proportion equation
   139,921.61 : 209,913.60 = 51,173.15 : x
2. Step 2: Convert to fraction form
   139,921.61/209,913.60 = 51,173.15/x
3. Step 3: Cross multiply
   139,921.61x = 209,913.60 × 51,173.15
4. Step 4: Simplify right side
   139,921.61x = 10,741,940,139.84
5. Step 5: Solve for x
   x = 10,741,940,139.84/139,921.61
6. Step 6: Final answer
   x = 76,771.13