Finding the Fourth Proportional to 3,783.86, 5,221.65 and 2,105.21

Step by Step Solution

1. Step 1: Write the proportion equation
   3,783.86 : 5,221.65 = 2,105.21 : x
2. Step 2: Convert to fraction form
   3,783.86/5,221.65 = 2,105.21/x
3. Step 3: Cross multiply
   3,783.86x = 5,221.65 × 2,105.21
4. Step 4: Simplify right side
   3,783.86x = 10,992,643.69
5. Step 5: Solve for x
   x = 10,992,643.69/3,783.86
6. Step 6: Final answer
   x = 2,905.14