Finding the Fourth Proportional to 9,139.26, 12,611.48 and 5,160.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,139.26 : 12,611.48 = 5,160.72 : x
2. Step 2: Convert to fraction form
   9,139.26/12,611.48 = 5,160.72/x
3. Step 3: Cross multiply
   9,139.26x = 12,611.48 × 5,160.72
4. Step 4: Simplify right side
   9,139.26x = 65,084,291.26
5. Step 5: Solve for x
   x = 65,084,291.26/9,139.26
6. Step 6: Final answer
   x = 7,121.40