Finding the Fourth Proportional to 20,871.69, 31,311.63 and 7,724.17

Step by Step Solution

1. Step 1: Write the proportion equation
   20,871.69 : 31,311.63 = 7,724.17 : x
2. Step 2: Convert to fraction form
   20,871.69/31,311.63 = 7,724.17/x
3. Step 3: Cross multiply
   20,871.69x = 31,311.63 × 7,724.17
4. Step 4: Simplify right side
   20,871.69x = 241,856,392.24
5. Step 5: Solve for x
   x = 241,856,392.24/20,871.69
6. Step 6: Final answer
   x = 11,587.77