Finding the Fourth Proportional to 13,205.20, 18,222.56 and 7,236.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,205.20 : 18,222.56 = 7,236.72 : x
2. Step 2: Convert to fraction form
   13,205.20/18,222.56 = 7,236.72/x
3. Step 3: Cross multiply
   13,205.20x = 18,222.56 × 7,236.72
4. Step 4: Simplify right side
   13,205.20x = 131,871,564.40
5. Step 5: Solve for x
   x = 131,871,564.40/13,205.20
6. Step 6: Final answer
   x = 9,986.34