Finding the Third Proportional to 80,640.50 and 128,111

Step by Step Solution

1. Step 1: Write the proportion equation
   80,640.50 : 128,111 = 128,111 : x
2. Step 2: Convert to fraction form
   80,640.50/128,111 = 128,111/x
3. Step 3: Cross multiply
   80,640.50x = 128,111 × 128,111
4. Step 4: Simplify right side
   80,640.50x = 16,412,428,321
5. Step 5: Solve for x
   x = 16,412,428,321/80,640.50
6. Step 6: Final answer
   x = 203,525.87