Finding the Third Proportional to 388.69 and 818.72

Step by Step Solution

1. Step 1: Write the proportion equation
   388.69 : 818.72 = 818.72 : x
2. Step 2: Convert to fraction form
   388.69/818.72 = 818.72/x
3. Step 3: Cross multiply
   388.69x = 818.72 × 818.72
4. Step 4: Simplify right side
   388.69x = 670,300.39
5. Step 5: Solve for x
   x = 670,300.39/388.69
6. Step 6: Final answer
   x = 1,724.52