Finding the Third Proportional to 289,830 and 443,390

Step by Step Solution

1. Step 1: Write the proportion equation
   289,830 : 443,390 = 443,390 : x
2. Step 2: Convert to fraction form
   289,830/443,390 = 443,390/x
3. Step 3: Cross multiply
   289,830x = 443,390 × 443,390
4. Step 4: Simplify right side
   289,830x = 196,594,692,100
5. Step 5: Solve for x
   x = 196,594,692,100/289,830
6. Step 6: Final answer
   x = 678,310.36