Finding the Fourth Proportional to 2,113.55, 3,171.20 and 1,291.85

Step by Step Solution

1. Step 1: Write the proportion equation
   2,113.55 : 3,171.20 = 1,291.85 : x
2. Step 2: Convert to fraction form
   2,113.55/3,171.20 = 1,291.85/x
3. Step 3: Cross multiply
   2,113.55x = 3,171.20 × 1,291.85
4. Step 4: Simplify right side
   2,113.55x = 4,096,692.40
5. Step 5: Solve for x
   x = 4,096,692.40/2,113.55
6. Step 6: Final answer
   x = 1,938.30