Finding the Third Proportional to 139,440 and 209,478

Step by Step Solution

1. Step 1: Write the proportion equation
   139,440 : 209,478 = 209,478 : x
2. Step 2: Convert to fraction form
   139,440/209,478 = 209,478/x
3. Step 3: Cross multiply
   139,440x = 209,478 × 209,478
4. Step 4: Simplify right side
   139,440x = 43,881,032,484
5. Step 5: Solve for x
   x = 43,881,032,484/139,440
6. Step 6: Final answer
   x = 314,694.73