Finding the Fourth Proportional to 20,570.46, 30,861.18 and 8,724.72

Step by Step Solution

1. Step 1: Write the proportion equation
   20,570.46 : 30,861.18 = 8,724.72 : x
2. Step 2: Convert to fraction form
   20,570.46/30,861.18 = 8,724.72/x
3. Step 3: Cross multiply
   20,570.46x = 30,861.18 × 8,724.72
4. Step 4: Simplify right side
   20,570.46x = 269,255,128.69
5. Step 5: Solve for x
   x = 269,255,128.69/20,570.46
6. Step 6: Final answer
   x = 13,089.40