Finding the Third Proportional to 666,408 and 1,439,256

Step by Step Solution

1. Step 1: Write the proportion equation
   666,408 : 1,439,256 = 1,439,256 : x
2. Step 2: Convert to fraction form
   666,408/1,439,256 = 1,439,256/x
3. Step 3: Cross multiply
   666,408x = 1,439,256 × 1,439,256
4. Step 4: Simplify right side
   666,408x = 2,071,457,833,536
5. Step 5: Solve for x
   x = 2,071,457,833,536/666,408
6. Step 6: Final answer
   x = 3,108,392.81