Finding the Third Proportional to 2,490.28 and 5,390.61

Step by Step Solution

1. Step 1: Write the proportion equation
   2,490.28 : 5,390.61 = 5,390.61 : x
2. Step 2: Convert to fraction form
   2,490.28/5,390.61 = 5,390.61/x
3. Step 3: Cross multiply
   2,490.28x = 5,390.61 × 5,390.61
4. Step 4: Simplify right side
   2,490.28x = 29,058,711.55
5. Step 5: Solve for x
   x = 29,058,711.55/2,490.28
6. Step 6: Final answer
   x = 11,668.87