Finding the Fourth Proportional to 3,783.80, 5,221.50 and 2,105.15

Step by Step Solution

1. Step 1: Write the proportion equation
   3,783.80 : 5,221.50 = 2,105.15 : x
2. Step 2: Convert to fraction form
   3,783.80/5,221.50 = 2,105.15/x
3. Step 3: Cross multiply
   3,783.80x = 5,221.50 × 2,105.15
4. Step 4: Simplify right side
   3,783.80x = 10,992,040.73
5. Step 5: Solve for x
   x = 10,992,040.73/3,783.80
6. Step 6: Final answer
   x = 2,905.03