Finding the Fourth Proportional to 139,156.62, 207,061.10 and 138,690.06

Step by Step Solution

1. Step 1: Write the proportion equation
   139,156.62 : 207,061.10 = 138,690.06 : x
2. Step 2: Convert to fraction form
   139,156.62/207,061.10 = 138,690.06/x
3. Step 3: Cross multiply
   139,156.62x = 207,061.10 × 138,690.06
4. Step 4: Simplify right side
   139,156.62x = 28,717,315,689.22
5. Step 5: Solve for x
   x = 28,717,315,689.22/139,156.62
6. Step 6: Final answer
   x = 206,366.87