Finding the Third Proportional to 5,128.31 and 10,413.56

Step by Step Solution

1. Step 1: Write the proportion equation
   5,128.31 : 10,413.56 = 10,413.56 : x
2. Step 2: Convert to fraction form
   5,128.31/10,413.56 = 10,413.56/x
3. Step 3: Cross multiply
   5,128.31x = 10,413.56 × 10,413.56
4. Step 4: Simplify right side
   5,128.31x = 108,442,283.94
5. Step 5: Solve for x
   x = 108,442,283.94/5,128.31
6. Step 6: Final answer
   x = 21,145.80