Finding the Third Proportional to 139.54 and 328.90

Step by Step Solution

1. Step 1: Write the proportion equation
   139.54 : 328.90 = 328.90 : x
2. Step 2: Convert to fraction form
   139.54/328.90 = 328.90/x
3. Step 3: Cross multiply
   139.54x = 328.90 × 328.90
4. Step 4: Simplify right side
   139.54x = 108,178.04
5. Step 5: Solve for x
   x = 108,178.04/139.54
6. Step 6: Final answer
   x = 775.27