Finding the Third Proportional to 139,606 and 310,172

Step by Step Solution

1. Step 1: Write the proportion equation
   139,606 : 310,172 = 310,172 : x
2. Step 2: Convert to fraction form
   139,606/310,172 = 310,172/x
3. Step 3: Cross multiply
   139,606x = 310,172 × 310,172
4. Step 4: Simplify right side
   139,606x = 96,206,669,584
5. Step 5: Solve for x
   x = 96,206,669,584/139,606
6. Step 6: Final answer
   x = 689,129.91