Finding the Third Proportional to 388.78 and 850.31

Step by Step Solution

1. Step 1: Write the proportion equation
   388.78 : 850.31 = 850.31 : x
2. Step 2: Convert to fraction form
   388.78/850.31 = 850.31/x
3. Step 3: Cross multiply
   388.78x = 850.31 × 850.31
4. Step 4: Simplify right side
   388.78x = 723,031.35
5. Step 5: Solve for x
   x = 723,031.35/388.78
6. Step 6: Final answer
   x = 1,859.74