Finding the Third Proportional to 249,477 and 390,906

Step by Step Solution

1. Step 1: Write the proportion equation
   249,477 : 390,906 = 390,906 : x
2. Step 2: Convert to fraction form
   249,477/390,906 = 390,906/x
3. Step 3: Cross multiply
   249,477x = 390,906 × 390,906
4. Step 4: Simplify right side
   249,477x = 152,807,500,836
5. Step 5: Solve for x
   x = 152,807,500,836/249,477
6. Step 6: Final answer
   x = 612,511.38