Finding the Third Proportional to 311,780 and 445,870

Step by Step Solution

1. Step 1: Write the proportion equation
   311,780 : 445,870 = 445,870 : x
2. Step 2: Convert to fraction form
   311,780/445,870 = 445,870/x
3. Step 3: Cross multiply
   311,780x = 445,870 × 445,870
4. Step 4: Simplify right side
   311,780x = 198,800,056,900
5. Step 5: Solve for x
   x = 198,800,056,900/311,780
6. Step 6: Final answer
   x = 637,629.28