Finding the Third Proportional to 40,689 and 56,020.50

Step by Step Solution

1. Step 1: Write the proportion equation
   40,689 : 56,020.50 = 56,020.50 : x
2. Step 2: Convert to fraction form
   40,689/56,020.50 = 56,020.50/x
3. Step 3: Cross multiply
   40,689x = 56,020.50 × 56,020.50
4. Step 4: Simplify right side
   40,689x = 3,138,296,420.25
5. Step 5: Solve for x
   x = 3,138,296,420.25/40,689
6. Step 6: Final answer
   x = 77,128.87