Finding the Fourth Proportional to 13,144.60, 18,139.31 and 7,479.23

Step by Step Solution

1. Step 1: Write the proportion equation
   13,144.60 : 18,139.31 = 7,479.23 : x
2. Step 2: Convert to fraction form
   13,144.60/18,139.31 = 7,479.23/x
3. Step 3: Cross multiply
   13,144.60x = 18,139.31 × 7,479.23
4. Step 4: Simplify right side
   13,144.60x = 135,667,980.83
5. Step 5: Solve for x
   x = 135,667,980.83/13,144.60
6. Step 6: Final answer
   x = 10,321.20