Finding the Fourth Proportional to 21,815.72, 32,772.78 and 13,056.78

Step by Step Solution

1. Step 1: Write the proportion equation
   21,815.72 : 32,772.78 = 13,056.78 : x
2. Step 2: Convert to fraction form
   21,815.72/32,772.78 = 13,056.78/x
3. Step 3: Cross multiply
   21,815.72x = 32,772.78 × 13,056.78
4. Step 4: Simplify right side
   21,815.72x = 427,906,978.45
5. Step 5: Solve for x
   x = 427,906,978.45/21,815.72
6. Step 6: Final answer
   x = 19,614.62