Finding the Fourth Proportional to 2,578.15, 3,557.79 and 1,428.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,578.15 : 3,557.79 = 1,428.31 : x
2. Step 2: Convert to fraction form
   2,578.15/3,557.79 = 1,428.31/x
3. Step 3: Cross multiply
   2,578.15x = 3,557.79 × 1,428.31
4. Step 4: Simplify right side
   2,578.15x = 5,081,627.03
5. Step 5: Solve for x
   x = 5,081,627.03/2,578.15
6. Step 6: Final answer
   x = 1,971.04