Finding the Fourth Proportional to 139,629.90, 207,865.50 and 138,799.50

Step by Step Solution

1. Step 1: Write the proportion equation
   139,629.90 : 207,865.50 = 138,799.50 : x
2. Step 2: Convert to fraction form
   139,629.90/207,865.50 = 138,799.50/x
3. Step 3: Cross multiply
   139,629.90x = 207,865.50 × 138,799.50
4. Step 4: Simplify right side
   139,629.90x = 28,851,627,467.25
5. Step 5: Solve for x
   x = 28,851,627,467.25/139,629.90
6. Step 6: Final answer
   x = 206,629.29