Finding the Fourth Proportional to 9,139.75, 12,611.49 and 5,160.77

Step by Step Solution

1. Step 1: Write the proportion equation
   9,139.75 : 12,611.49 = 5,160.77 : x
2. Step 2: Convert to fraction form
   9,139.75/12,611.49 = 5,160.77/x
3. Step 3: Cross multiply
   9,139.75x = 12,611.49 × 5,160.77
4. Step 4: Simplify right side
   9,139.75x = 65,084,999.25
5. Step 5: Solve for x
   x = 65,084,999.25/9,139.75
6. Step 6: Final answer
   x = 7,121.09