Finding the Third Proportional to 391.88 and 609.38

Step by Step Solution

1. Step 1: Write the proportion equation
   391.88 : 609.38 = 609.38 : x
2. Step 2: Convert to fraction form
   391.88/609.38 = 609.38/x
3. Step 3: Cross multiply
   391.88x = 609.38 × 609.38
4. Step 4: Simplify right side
   391.88x = 371,337.89
5. Step 5: Solve for x
   x = 371,337.89/391.88
6. Step 6: Final answer
   x = 947.59