Finding the Fourth Proportional to 13,162.72, 18,165.42 and 7,421.60

Step by Step Solution

1. Step 1: Write the proportion equation
   13,162.72 : 18,165.42 = 7,421.60 : x
2. Step 2: Convert to fraction form
   13,162.72/18,165.42 = 7,421.60/x
3. Step 3: Cross multiply
   13,162.72x = 18,165.42 × 7,421.60
4. Step 4: Simplify right side
   13,162.72x = 134,816,481.07
5. Step 5: Solve for x
   x = 134,816,481.07/13,162.72
6. Step 6: Final answer
   x = 10,242.30