Finding the Third Proportional to 321.47 and 699.89

Step by Step Solution

1. Step 1: Write the proportion equation
   321.47 : 699.89 = 699.89 : x
2. Step 2: Convert to fraction form
   321.47/699.89 = 699.89/x
3. Step 3: Cross multiply
   321.47x = 699.89 × 699.89
4. Step 4: Simplify right side
   321.47x = 489,846.89
5. Step 5: Solve for x
   x = 489,846.89/321.47
6. Step 6: Final answer
   x = 1,523.78