Finding the Third Proportional to 5,128.50 and 10,689

Step by Step Solution

1. Step 1: Write the proportion equation
   5,128.50 : 10,689 = 10,689 : x
2. Step 2: Convert to fraction form
   5,128.50/10,689 = 10,689/x
3. Step 3: Cross multiply
   5,128.50x = 10,689 × 10,689
4. Step 4: Simplify right side
   5,128.50x = 114,254,721
5. Step 5: Solve for x
   x = 114,254,721/5,128.50
6. Step 6: Final answer
   x = 22,278.39