Finding the Third Proportional to 149,400 and 321,456

Step by Step Solution

1. Step 1: Write the proportion equation
   149,400 : 321,456 = 321,456 : x
2. Step 2: Convert to fraction form
   149,400/321,456 = 321,456/x
3. Step 3: Cross multiply
   149,400x = 321,456 × 321,456
4. Step 4: Simplify right side
   149,400x = 103,333,959,936
5. Step 5: Solve for x
   x = 103,333,959,936/149,400
6. Step 6: Final answer
   x = 691,659.71