Finding the Fourth Proportional to 2,111.78, 2,913.36 and 1,439.48

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.78 : 2,913.36 = 1,439.48 : x
2. Step 2: Convert to fraction form
   2,111.78/2,913.36 = 1,439.48/x
3. Step 3: Cross multiply
   2,111.78x = 2,913.36 × 1,439.48
4. Step 4: Simplify right side
   2,111.78x = 4,193,723.45
5. Step 5: Solve for x
   x = 4,193,723.45/2,111.78
6. Step 6: Final answer
   x = 1,985.87