Finding the Third Proportional to 78,010.50 and 128,140.50

Step by Step Solution

1. Step 1: Write the proportion equation
   78,010.50 : 128,140.50 = 128,140.50 : x
2. Step 2: Convert to fraction form
   78,010.50/128,140.50 = 128,140.50/x
3. Step 3: Cross multiply
   78,010.50x = 128,140.50 × 128,140.50
4. Step 4: Simplify right side
   78,010.50x = 16,419,987,740.25
5. Step 5: Solve for x
   x = 16,419,987,740.25/78,010.50
6. Step 6: Final answer
   x = 210,484.33