Finding the Third Proportional to 57,720 and 86,581.50

Step by Step Solution

1. Step 1: Write the proportion equation
   57,720 : 86,581.50 = 86,581.50 : x
2. Step 2: Convert to fraction form
   57,720/86,581.50 = 86,581.50/x
3. Step 3: Cross multiply
   57,720x = 86,581.50 × 86,581.50
4. Step 4: Simplify right side
   57,720x = 7,496,356,142.25
5. Step 5: Solve for x
   x = 7,496,356,142.25/57,720
6. Step 6: Final answer
   x = 129,874.50