Finding the Third Proportional to 138,780 and 308,616

Step by Step Solution

1. Step 1: Write the proportion equation
   138,780 : 308,616 = 308,616 : x
2. Step 2: Convert to fraction form
   138,780/308,616 = 308,616/x
3. Step 3: Cross multiply
   138,780x = 308,616 × 308,616
4. Step 4: Simplify right side
   138,780x = 95,243,835,456
5. Step 5: Solve for x
   x = 95,243,835,456/138,780
6. Step 6: Final answer
   x = 686,293.67