Finding the Third Proportional to 3,912.19 and 8,488.69

Step by Step Solution

1. Step 1: Write the proportion equation
   3,912.19 : 8,488.69 = 8,488.69 : x
2. Step 2: Convert to fraction form
   3,912.19/8,488.69 = 8,488.69/x
3. Step 3: Cross multiply
   3,912.19x = 8,488.69 × 8,488.69
4. Step 4: Simplify right side
   3,912.19x = 72,057,815.47
5. Step 5: Solve for x
   x = 72,057,815.47/3,912.19
6. Step 6: Final answer
   x = 18,418.80