Finding the Third Proportional to 128,085.75 and 220,081.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128,085.75 : 220,081.50 = 220,081.50 : x
2. Step 2: Convert to fraction form
   128,085.75/220,081.50 = 220,081.50/x
3. Step 3: Cross multiply
   128,085.75x = 220,081.50 × 220,081.50
4. Step 4: Simplify right side
   128,085.75x = 48,435,866,642.25
5. Step 5: Solve for x
   x = 48,435,866,642.25/128,085.75
6. Step 6: Final answer
   x = 378,151.88