Finding the Fourth Proportional to 139,288.59, 209,052.15 and 138,240.18

Step by Step Solution

1. Step 1: Write the proportion equation
   139,288.59 : 209,052.15 = 138,240.18 : x
2. Step 2: Convert to fraction form
   139,288.59/209,052.15 = 138,240.18/x
3. Step 3: Cross multiply
   139,288.59x = 209,052.15 × 138,240.18
4. Step 4: Simplify right side
   139,288.59x = 28,899,406,845.39
5. Step 5: Solve for x
   x = 28,899,406,845.39/139,288.59
6. Step 6: Final answer
   x = 207,478.64