Finding the Fourth Proportional to 12,720.24, 17,553.72 and 7,131.12

Step by Step Solution

1. Step 1: Write the proportion equation
   12,720.24 : 17,553.72 = 7,131.12 : x
2. Step 2: Convert to fraction form
   12,720.24/17,553.72 = 7,131.12/x
3. Step 3: Cross multiply
   12,720.24x = 17,553.72 × 7,131.12
4. Step 4: Simplify right side
   12,720.24x = 125,177,683.77
5. Step 5: Solve for x
   x = 125,177,683.77/12,720.24
6. Step 6: Final answer
   x = 9,840.83