Finding the Fourth Proportional to 13,144.95, 18,139.79 and 7,479.57

Step by Step Solution

1. Step 1: Write the proportion equation
   13,144.95 : 18,139.79 = 7,479.57 : x
2. Step 2: Convert to fraction form
   13,144.95/18,139.79 = 7,479.57/x
3. Step 3: Cross multiply
   13,144.95x = 18,139.79 × 7,479.57
4. Step 4: Simplify right side
   13,144.95x = 135,677,791.69
5. Step 5: Solve for x
   x = 135,677,791.69/13,144.95
6. Step 6: Final answer
   x = 10,321.67