Finding the Fourth Proportional to 2,661.41, 3,990.80 and 1,101.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,661.41 : 3,990.80 = 1,101.55 : x
2. Step 2: Convert to fraction form
   2,661.41/3,990.80 = 1,101.55/x
3. Step 3: Cross multiply
   2,661.41x = 3,990.80 × 1,101.55
4. Step 4: Simplify right side
   2,661.41x = 4,396,065.74
5. Step 5: Solve for x
   x = 4,396,065.74/2,661.41
6. Step 6: Final answer
   x = 1,651.78