Finding the Third Proportional to 218,439 and 309,433.50

Step by Step Solution

1. Step 1: Write the proportion equation
   218,439 : 309,433.50 = 309,433.50 : x
2. Step 2: Convert to fraction form
   218,439/309,433.50 = 309,433.50/x
3. Step 3: Cross multiply
   218,439x = 309,433.50 × 309,433.50
4. Step 4: Simplify right side
   218,439x = 95,749,090,922.25
5. Step 5: Solve for x
   x = 95,749,090,922.25/218,439
6. Step 6: Final answer
   x = 438,333.31