Finding the Third Proportional to 315.56 and 669.38

Step by Step Solution

1. Step 1: Write the proportion equation
   315.56 : 669.38 = 669.38 : x
2. Step 2: Convert to fraction form
   315.56/669.38 = 669.38/x
3. Step 3: Cross multiply
   315.56x = 669.38 × 669.38
4. Step 4: Simplify right side
   315.56x = 448,062.89
5. Step 5: Solve for x
   x = 448,062.89/315.56
6. Step 6: Final answer
   x = 1,419.89