Finding the Third Proportional to 388.69 and 662.63

Step by Step Solution

1. Step 1: Write the proportion equation
   388.69 : 662.63 = 662.63 : x
2. Step 2: Convert to fraction form
   388.69/662.63 = 662.63/x
3. Step 3: Cross multiply
   388.69x = 662.63 × 662.63
4. Step 4: Simplify right side
   388.69x = 439,071.89
5. Step 5: Solve for x
   x = 439,071.89/388.69
6. Step 6: Final answer
   x = 1,129.63