Finding the Third Proportional to 388.50 and 851.50

Step by Step Solution

1. Step 1: Write the proportion equation
   388.50 : 851.50 = 851.50 : x
2. Step 2: Convert to fraction form
   388.50/851.50 = 851.50/x
3. Step 3: Cross multiply
   388.50x = 851.50 × 851.50
4. Step 4: Simplify right side
   388.50x = 725,052.25
5. Step 5: Solve for x
   x = 725,052.25/388.50
6. Step 6: Final answer
   x = 1,866.29