Finding the Fourth Proportional to 3,911.58, 5,861.30 and 2,155.10

Step by Step Solution

1. Step 1: Write the proportion equation
   3,911.58 : 5,861.30 = 2,155.10 : x
2. Step 2: Convert to fraction form
   3,911.58/5,861.30 = 2,155.10/x
3. Step 3: Cross multiply
   3,911.58x = 5,861.30 × 2,155.10
4. Step 4: Simplify right side
   3,911.58x = 12,631,647.55
5. Step 5: Solve for x
   x = 12,631,647.55/3,911.58
6. Step 6: Final answer
   x = 3,229.30