Finding the Third Proportional to 138,796 and 308,648

Step by Step Solution

1. Step 1: Write the proportion equation
   138,796 : 308,648 = 308,648 : x
2. Step 2: Convert to fraction form
   138,796/308,648 = 308,648/x
3. Step 3: Cross multiply
   138,796x = 308,648 × 308,648
4. Step 4: Simplify right side
   138,796x = 95,263,587,904
5. Step 5: Solve for x
   x = 95,263,587,904/138,796
6. Step 6: Final answer
   x = 686,356.87