Finding the Third Proportional to 63,990 and 72,009

Step by Step Solution

1. Step 1: Write the proportion equation
   63,990 : 72,009 = 72,009 : x
2. Step 2: Convert to fraction form
   63,990/72,009 = 72,009/x
3. Step 3: Cross multiply
   63,990x = 72,009 × 72,009
4. Step 4: Simplify right side
   63,990x = 5,185,296,081
5. Step 5: Solve for x
   x = 5,185,296,081/63,990
6. Step 6: Final answer
   x = 81,032.91