Finding the Fourth Proportional to 12,840.50, 17,721.78 and 7,538.24

Step by Step Solution

1. Step 1: Write the proportion equation
   12,840.50 : 17,721.78 = 7,538.24 : x
2. Step 2: Convert to fraction form
   12,840.50/17,721.78 = 7,538.24/x
3. Step 3: Cross multiply
   12,840.50x = 17,721.78 × 7,538.24
4. Step 4: Simplify right side
   12,840.50x = 133,591,030.87
5. Step 5: Solve for x
   x = 133,591,030.87/12,840.50
6. Step 6: Final answer
   x = 10,403.88