Finding the Third Proportional to 243,189 and 388,500.75

Step by Step Solution

1. Step 1: Write the proportion equation
   243,189 : 388,500.75 = 388,500.75 : x
2. Step 2: Convert to fraction form
   243,189/388,500.75 = 388,500.75/x
3. Step 3: Cross multiply
   243,189x = 388,500.75 × 388,500.75
4. Step 4: Simplify right side
   243,189x = 150,932,832,750.56
5. Step 5: Solve for x
   x = 150,932,832,750.56/243,189
6. Step 6: Final answer
   x = 620,640.05