Finding the Third Proportional to 8,290.69 and 11,721.38

Step by Step Solution

1. Step 1: Write the proportion equation
   8,290.69 : 11,721.38 = 11,721.38 : x
2. Step 2: Convert to fraction form
   8,290.69/11,721.38 = 11,721.38/x
3. Step 3: Cross multiply
   8,290.69x = 11,721.38 × 11,721.38
4. Step 4: Simplify right side
   8,290.69x = 137,390,631.89
5. Step 5: Solve for x
   x = 137,390,631.89/8,290.69
6. Step 6: Final answer
   x = 16,571.68