Finding the Fourth Proportional to 3,699.89, 5,105.68 and 2,021.21

Step by Step Solution

1. Step 1: Write the proportion equation
   3,699.89 : 5,105.68 = 2,021.21 : x
2. Step 2: Convert to fraction form
   3,699.89/5,105.68 = 2,021.21/x
3. Step 3: Cross multiply
   3,699.89x = 5,105.68 × 2,021.21
4. Step 4: Simplify right side
   3,699.89x = 10,319,665.77
5. Step 5: Solve for x
   x = 10,319,665.77/3,699.89
6. Step 6: Final answer
   x = 2,789.18