Finding the Third Proportional to 5,139.70 and 7,689.30

Step by Step Solution

1. Step 1: Write the proportion equation
   5,139.70 : 7,689.30 = 7,689.30 : x
2. Step 2: Convert to fraction form
   5,139.70/7,689.30 = 7,689.30/x
3. Step 3: Cross multiply
   5,139.70x = 7,689.30 × 7,689.30
4. Step 4: Simplify right side
   5,139.70x = 59,125,406.58
5. Step 5: Solve for x
   x = 59,125,406.58/5,139.70
6. Step 6: Final answer
   x = 11,503.66