Finding the Fourth Proportional to 11,721.51, 17,578.62 and 3,928.50

Step by Step Solution

1. Step 1: Write the proportion equation
   11,721.51 : 17,578.62 = 3,928.50 : x
2. Step 2: Convert to fraction form
   11,721.51/17,578.62 = 3,928.50/x
3. Step 3: Cross multiply
   11,721.51x = 17,578.62 × 3,928.50
4. Step 4: Simplify right side
   11,721.51x = 69,057,608.67
5. Step 5: Solve for x
   x = 69,057,608.67/11,721.51
6. Step 6: Final answer
   x = 5,891.53