Finding the Third Proportional to 321,174.50 and 691,678

Step by Step Solution

1. Step 1: Write the proportion equation
   321,174.50 : 691,678 = 691,678 : x
2. Step 2: Convert to fraction form
   321,174.50/691,678 = 691,678/x
3. Step 3: Cross multiply
   321,174.50x = 691,678 × 691,678
4. Step 4: Simplify right side
   321,174.50x = 478,418,455,684
5. Step 5: Solve for x
   x = 478,418,455,684/321,174.50
6. Step 6: Final answer
   x = 1,489,590.41