Finding the Third Proportional to 78,663 and 172,878

Step by Step Solution

1. Step 1: Write the proportion equation
   78,663 : 172,878 = 172,878 : x
2. Step 2: Convert to fraction form
   78,663/172,878 = 172,878/x
3. Step 3: Cross multiply
   78,663x = 172,878 × 172,878
4. Step 4: Simplify right side
   78,663x = 29,886,802,884
5. Step 5: Solve for x
   x = 29,886,802,884/78,663
6. Step 6: Final answer
   x = 379,934.69