Finding the Third Proportional to 388.71 and 856.43

Step by Step Solution

1. Step 1: Write the proportion equation
   388.71 : 856.43 = 856.43 : x
2. Step 2: Convert to fraction form
   388.71/856.43 = 856.43/x
3. Step 3: Cross multiply
   388.71x = 856.43 × 856.43
4. Step 4: Simplify right side
   388.71x = 733,476.83
5. Step 5: Solve for x
   x = 733,476.83/388.71
6. Step 6: Final answer
   x = 1,886.98