Finding the Third Proportional to 208.78 and 404.06

Step by Step Solution

1. Step 1: Write the proportion equation
   208.78 : 404.06 = 404.06 : x
2. Step 2: Convert to fraction form
   208.78/404.06 = 404.06/x
3. Step 3: Cross multiply
   208.78x = 404.06 × 404.06
4. Step 4: Simplify right side
   208.78x = 163,266.50
5. Step 5: Solve for x
   x = 163,266.50/208.78
6. Step 6: Final answer
   x = 782.00