Finding the Third Proportional to 166.78 and 328.78

Step by Step Solution

1. Step 1: Write the proportion equation
   166.78 : 328.78 = 328.78 : x
2. Step 2: Convert to fraction form
   166.78/328.78 = 328.78/x
3. Step 3: Cross multiply
   166.78x = 328.78 × 328.78
4. Step 4: Simplify right side
   166.78x = 108,097.11
5. Step 5: Solve for x
   x = 108,097.11/166.78
6. Step 6: Final answer
   x = 648.14