Finding the Third Proportional to 5,439.94 and 8,139.38

Step by Step Solution

1. Step 1: Write the proportion equation
   5,439.94 : 8,139.38 = 8,139.38 : x
2. Step 2: Convert to fraction form
   5,439.94/8,139.38 = 8,139.38/x
3. Step 3: Cross multiply
   5,439.94x = 8,139.38 × 8,139.38
4. Step 4: Simplify right side
   5,439.94x = 66,249,425.39
5. Step 5: Solve for x
   x = 66,249,425.39/5,439.94
6. Step 6: Final answer
   x = 12,178.34