Finding the Fourth Proportional to 21,856.27, 30,160.76 and 12,906.65

Step by Step Solution

1. Step 1: Write the proportion equation
   21,856.27 : 30,160.76 = 12,906.65 : x
2. Step 2: Convert to fraction form
   21,856.27/30,160.76 = 12,906.65/x
3. Step 3: Cross multiply
   21,856.27x = 30,160.76 × 12,906.65
4. Step 4: Simplify right side
   21,856.27x = 389,274,373.05
5. Step 5: Solve for x
   x = 389,274,373.05/21,856.27
6. Step 6: Final answer
   x = 17,810.65