Finding the Third Proportional to 39,920 and 55,505

Step by Step Solution

1. Step 1: Write the proportion equation
   39,920 : 55,505 = 55,505 : x
2. Step 2: Convert to fraction form
   39,920/55,505 = 55,505/x
3. Step 3: Cross multiply
   39,920x = 55,505 × 55,505
4. Step 4: Simplify right side
   39,920x = 3,080,805,025
5. Step 5: Solve for x
   x = 3,080,805,025/39,920
6. Step 6: Final answer
   x = 77,174.47