Finding the Third Proportional to 3,138 and 3,978

Step by Step Solution

1. Step 1: Write the proportion equation
   3,138 : 3,978 = 3,978 : x
2. Step 2: Convert to fraction form
   3,138/3,978 = 3,978/x
3. Step 3: Cross multiply
   3,138x = 3,978 × 3,978
4. Step 4: Simplify right side
   3,138x = 15,824,484
5. Step 5: Solve for x
   x = 15,824,484/3,138
6. Step 6: Final answer
   x = 5,042.86