Finding the Third Proportional to 138,911 and 207,451.50

Step by Step Solution

1. Step 1: Write the proportion equation
   138,911 : 207,451.50 = 207,451.50 : x
2. Step 2: Convert to fraction form
   138,911/207,451.50 = 207,451.50/x
3. Step 3: Cross multiply
   138,911x = 207,451.50 × 207,451.50
4. Step 4: Simplify right side
   138,911x = 43,036,124,852.25
5. Step 5: Solve for x
   x = 43,036,124,852.25/138,911
6. Step 6: Final answer
   x = 309,810.78