Finding the Fourth Proportional to 139,628.89, 207,864 and 138,798.51

Step by Step Solution

1. Step 1: Write the proportion equation
   139,628.89 : 207,864 = 138,798.51 : x
2. Step 2: Convert to fraction form
   139,628.89/207,864 = 138,798.51/x
3. Step 3: Cross multiply
   139,628.89x = 207,864 × 138,798.51
4. Step 4: Simplify right side
   139,628.89x = 28,851,213,482.64
5. Step 5: Solve for x
   x = 28,851,213,482.64/139,628.89
6. Step 6: Final answer
   x = 206,627.82