Finding the Third Proportional to 219,870 and 328,505

Step by Step Solution

1. Step 1: Write the proportion equation
   219,870 : 328,505 = 328,505 : x
2. Step 2: Convert to fraction form
   219,870/328,505 = 328,505/x
3. Step 3: Cross multiply
   219,870x = 328,505 × 328,505
4. Step 4: Simplify right side
   219,870x = 107,915,535,025
5. Step 5: Solve for x
   x = 107,915,535,025/219,870
6. Step 6: Final answer
   x = 490,815.19