Finding the Third Proportional to 129,721.50 and 279,450

Step by Step Solution

1. Step 1: Write the proportion equation
   129,721.50 : 279,450 = 279,450 : x
2. Step 2: Convert to fraction form
   129,721.50/279,450 = 279,450/x
3. Step 3: Cross multiply
   129,721.50x = 279,450 × 279,450
4. Step 4: Simplify right side
   129,721.50x = 78,092,302,500
5. Step 5: Solve for x
   x = 78,092,302,500/129,721.50
6. Step 6: Final answer
   x = 601,999.69