Finding the Third Proportional to 290,189 and 443,870

Step by Step Solution

1. Step 1: Write the proportion equation
   290,189 : 443,870 = 443,870 : x
2. Step 2: Convert to fraction form
   290,189/443,870 = 443,870/x
3. Step 3: Cross multiply
   290,189x = 443,870 × 443,870
4. Step 4: Simplify right side
   290,189x = 197,020,576,900
5. Step 5: Solve for x
   x = 197,020,576,900/290,189
6. Step 6: Final answer
   x = 678,938.82