Finding the Fourth Proportional to 21,800.81, 30,080.46 and 12,845.05

Step by Step Solution

1. Step 1: Write the proportion equation
   21,800.81 : 30,080.46 = 12,845.05 : x
2. Step 2: Convert to fraction form
   21,800.81/30,080.46 = 12,845.05/x
3. Step 3: Cross multiply
   21,800.81x = 30,080.46 × 12,845.05
4. Step 4: Simplify right side
   21,800.81x = 386,384,985.69
5. Step 5: Solve for x
   x = 386,384,985.69/21,800.81
6. Step 6: Final answer
   x = 17,723.42