Finding the Third Proportional to 78,831 and 172,991.25

Step by Step Solution

1. Step 1: Write the proportion equation
   78,831 : 172,991.25 = 172,991.25 : x
2. Step 2: Convert to fraction form
   78,831/172,991.25 = 172,991.25/x
3. Step 3: Cross multiply
   78,831x = 172,991.25 × 172,991.25
4. Step 4: Simplify right side
   78,831x = 29,925,972,576.56
5. Step 5: Solve for x
   x = 29,925,972,576.56/78,831
6. Step 6: Final answer
   x = 379,621.88