Finding the Third Proportional to 3,121.50 and 3,960

Step by Step Solution

1. Step 1: Write the proportion equation
   3,121.50 : 3,960 = 3,960 : x
2. Step 2: Convert to fraction form
   3,121.50/3,960 = 3,960/x
3. Step 3: Cross multiply
   3,121.50x = 3,960 × 3,960
4. Step 4: Simplify right side
   3,121.50x = 15,681,600
5. Step 5: Solve for x
   x = 15,681,600/3,121.50
6. Step 6: Final answer
   x = 5,023.74