Finding the Third Proportional to 111,129 and 172,120.50

Step by Step Solution

1. Step 1: Write the proportion equation
   111,129 : 172,120.50 = 172,120.50 : x
2. Step 2: Convert to fraction form
   111,129/172,120.50 = 172,120.50/x
3. Step 3: Cross multiply
   111,129x = 172,120.50 × 172,120.50
4. Step 4: Simplify right side
   111,129x = 29,625,466,520.25
5. Step 5: Solve for x
   x = 29,625,466,520.25/111,129
6. Step 6: Final answer
   x = 266,586.28