Finding the Fourth Proportional to 15,721.52, 21,726.81 and 12,884.42

Step by Step Solution

1. Step 1: Write the proportion equation
   15,721.52 : 21,726.81 = 12,884.42 : x
2. Step 2: Convert to fraction form
   15,721.52/21,726.81 = 12,884.42/x
3. Step 3: Cross multiply
   15,721.52x = 21,726.81 × 12,884.42
4. Step 4: Simplify right side
   15,721.52x = 279,937,345.30
5. Step 5: Solve for x
   x = 279,937,345.30/15,721.52
6. Step 6: Final answer
   x = 17,806.00