Finding the Fourth Proportional to 3,978.72, 5,490.65 and 2,210.66

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.72 : 5,490.65 = 2,210.66 : x
2. Step 2: Convert to fraction form
   3,978.72/5,490.65 = 2,210.66/x
3. Step 3: Cross multiply
   3,978.72x = 5,490.65 × 2,210.66
4. Step 4: Simplify right side
   3,978.72x = 12,137,921.82
5. Step 5: Solve for x
   x = 12,137,921.82/3,978.72
6. Step 6: Final answer
   x = 3,050.71