Finding the Fourth Proportional to 2,557.11, 3,528.79 and 1,438.05

Step by Step Solution

1. Step 1: Write the proportion equation
   2,557.11 : 3,528.79 = 1,438.05 : x
2. Step 2: Convert to fraction form
   2,557.11/3,528.79 = 1,438.05/x
3. Step 3: Cross multiply
   2,557.11x = 3,528.79 × 1,438.05
4. Step 4: Simplify right side
   2,557.11x = 5,074,576.46
5. Step 5: Solve for x
   x = 5,074,576.46/2,557.11
6. Step 6: Final answer
   x = 1,984.50