Finding the Fourth Proportional to 139,156.12, 207,060.35 and 138,689.56

Step by Step Solution

1. Step 1: Write the proportion equation
   139,156.12 : 207,060.35 = 138,689.56 : x
2. Step 2: Convert to fraction form
   139,156.12/207,060.35 = 138,689.56/x
3. Step 3: Cross multiply
   139,156.12x = 207,060.35 × 138,689.56
4. Step 4: Simplify right side
   139,156.12x = 28,717,108,834.95
5. Step 5: Solve for x
   x = 28,717,108,834.95/139,156.12
6. Step 6: Final answer
   x = 206,366.12