Finding the Fourth Proportional to 13,391.69, 18,479.80 and 7,726.10

Step by Step Solution

1. Step 1: Write the proportion equation
   13,391.69 : 18,479.80 = 7,726.10 : x
2. Step 2: Convert to fraction form
   13,391.69/18,479.80 = 7,726.10/x
3. Step 3: Cross multiply
   13,391.69x = 18,479.80 × 7,726.10
4. Step 4: Simplify right side
   13,391.69x = 142,776,700.04
5. Step 5: Solve for x
   x = 142,776,700.04/13,391.69
6. Step 6: Final answer
   x = 10,661.59