Finding the Fourth Proportional to 3,128.15, 4,690.53 and 1,278.32

Step by Step Solution

1. Step 1: Write the proportion equation
   3,128.15 : 4,690.53 = 1,278.32 : x
2. Step 2: Convert to fraction form
   3,128.15/4,690.53 = 1,278.32/x
3. Step 3: Cross multiply
   3,128.15x = 4,690.53 × 1,278.32
4. Step 4: Simplify right side
   3,128.15x = 5,995,974.86
5. Step 5: Solve for x
   x = 5,995,974.86/3,128.15
6. Step 6: Final answer
   x = 1,916.78