Finding the Third Proportional to 83,128.78 and 172,169.30

Step by Step Solution

1. Step 1: Write the proportion equation
   83,128.78 : 172,169.30 = 172,169.30 : x
2. Step 2: Convert to fraction form
   83,128.78/172,169.30 = 172,169.30/x
3. Step 3: Cross multiply
   83,128.78x = 172,169.30 × 172,169.30
4. Step 4: Simplify right side
   83,128.78x = 29,642,266,786.43
5. Step 5: Solve for x
   x = 29,642,266,786.43/83,128.78
6. Step 6: Final answer
   x = 356,582.48