Finding the Third Proportional to 138,792 and 308,640

Step by Step Solution

1. Step 1: Write the proportion equation
   138,792 : 308,640 = 308,640 : x
2. Step 2: Convert to fraction form
   138,792/308,640 = 308,640/x
3. Step 3: Cross multiply
   138,792x = 308,640 × 308,640
4. Step 4: Simplify right side
   138,792x = 95,258,649,600
5. Step 5: Solve for x
   x = 95,258,649,600/138,792
6. Step 6: Final answer
   x = 686,341.07