Finding the Fourth Proportional to 15,760.71, 21,748.59 and 8,687.16

Step by Step Solution

1. Step 1: Write the proportion equation
   15,760.71 : 21,748.59 = 8,687.16 : x
2. Step 2: Convert to fraction form
   15,760.71/21,748.59 = 8,687.16/x
3. Step 3: Cross multiply
   15,760.71x = 21,748.59 × 8,687.16
4. Step 4: Simplify right side
   15,760.71x = 188,933,481.10
5. Step 5: Solve for x
   x = 188,933,481.10/15,760.71
6. Step 6: Final answer
   x = 11,987.62