Finding the Third Proportional to 3,939 and 5,128.50

Step by Step Solution

1. Step 1: Write the proportion equation
   3,939 : 5,128.50 = 5,128.50 : x
2. Step 2: Convert to fraction form
   3,939/5,128.50 = 5,128.50/x
3. Step 3: Cross multiply
   3,939x = 5,128.50 × 5,128.50
4. Step 4: Simplify right side
   3,939x = 26,301,512.25
5. Step 5: Solve for x
   x = 26,301,512.25/3,939
6. Step 6: Final answer
   x = 6,677.21