Finding the Third Proportional to 138,406.50 and 206,886

Step by Step Solution

1. Step 1: Write the proportion equation
   138,406.50 : 206,886 = 206,886 : x
2. Step 2: Convert to fraction form
   138,406.50/206,886 = 206,886/x
3. Step 3: Cross multiply
   138,406.50x = 206,886 × 206,886
4. Step 4: Simplify right side
   138,406.50x = 42,801,816,996
5. Step 5: Solve for x
   x = 42,801,816,996/138,406.50
6. Step 6: Final answer
   x = 309,247.16