Finding the Fourth Proportional to 13,144.28, 18,139.57 and 7,479.89

Step by Step Solution

1. Step 1: Write the proportion equation
   13,144.28 : 18,139.57 = 7,479.89 : x
2. Step 2: Convert to fraction form
   13,144.28/18,139.57 = 7,479.89/x
3. Step 3: Cross multiply
   13,144.28x = 18,139.57 × 7,479.89
4. Step 4: Simplify right side
   13,144.28x = 135,681,878.85
5. Step 5: Solve for x
   x = 135,681,878.85/13,144.28
6. Step 6: Final answer
   x = 10,322.50