Finding the Third Proportional to 399.38 and 561.94

Step by Step Solution

1. Step 1: Write the proportion equation
   399.38 : 561.94 = 561.94 : x
2. Step 2: Convert to fraction form
   399.38/561.94 = 561.94/x
3. Step 3: Cross multiply
   399.38x = 561.94 × 561.94
4. Step 4: Simplify right side
   399.38x = 315,773.75
5. Step 5: Solve for x
   x = 315,773.75/399.38
6. Step 6: Final answer
   x = 790.67