Finding the Third Proportional to 218,361 and 309,316.50

Step by Step Solution

1. Step 1: Write the proportion equation
   218,361 : 309,316.50 = 309,316.50 : x
2. Step 2: Convert to fraction form
   218,361/309,316.50 = 309,316.50/x
3. Step 3: Cross multiply
   218,361x = 309,316.50 × 309,316.50
4. Step 4: Simplify right side
   218,361x = 95,676,697,172.25
5. Step 5: Solve for x
   x = 95,676,697,172.25/218,361
6. Step 6: Final answer
   x = 438,158.36