Finding the Third Proportional to 1,215,990 and 2,639,664

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215,990 : 2,639,664 = 2,639,664 : x
2. Step 2: Convert to fraction form
   1,215,990/2,639,664 = 2,639,664/x
3. Step 3: Cross multiply
   1,215,990x = 2,639,664 × 2,639,664
4. Step 4: Simplify right side
   1,215,990x = 6,967,826,032,896
5. Step 5: Solve for x
   x = 6,967,826,032,896/1,215,990
6. Step 6: Final answer
   x = 5,730,167.22