Finding the Third Proportional to 643,898 and 1,388,215

Step by Step Solution

1. Step 1: Write the proportion equation
   643,898 : 1,388,215 = 1,388,215 : x
2. Step 2: Convert to fraction form
   643,898/1,388,215 = 1,388,215/x
3. Step 3: Cross multiply
   643,898x = 1,388,215 × 1,388,215
4. Step 4: Simplify right side
   643,898x = 1,927,140,886,225
5. Step 5: Solve for x
   x = 1,927,140,886,225/643,898
6. Step 6: Final answer
   x = 2,992,928.83