Finding the Third Proportional to 388.13 and 613.31

Step by Step Solution

1. Step 1: Write the proportion equation
   388.13 : 613.31 = 613.31 : x
2. Step 2: Convert to fraction form
   388.13/613.31 = 613.31/x
3. Step 3: Cross multiply
   388.13x = 613.31 × 613.31
4. Step 4: Simplify right side
   388.13x = 376,152.22
5. Step 5: Solve for x
   x = 376,152.22/388.13
6. Step 6: Final answer
   x = 969.15