Finding the Fourth Proportional to 13,196.80, 18,211.60 and 7,228.57

Step by Step Solution

1. Step 1: Write the proportion equation
   13,196.80 : 18,211.60 = 7,228.57 : x
2. Step 2: Convert to fraction form
   13,196.80/18,211.60 = 7,228.57/x
3. Step 3: Cross multiply
   13,196.80x = 18,211.60 × 7,228.57
4. Step 4: Simplify right side
   13,196.80x = 131,643,789.27
5. Step 5: Solve for x
   x = 131,643,789.27/13,196.80
6. Step 6: Final answer
   x = 9,975.43