Finding the Fourth Proportional to 2,665.35, 3,998.43 and 1,278.43

Step by Step Solution

1. Step 1: Write the proportion equation
   2,665.35 : 3,998.43 = 1,278.43 : x
2. Step 2: Convert to fraction form
   2,665.35/3,998.43 = 1,278.43/x
3. Step 3: Cross multiply
   2,665.35x = 3,998.43 × 1,278.43
4. Step 4: Simplify right side
   2,665.35x = 5,111,702.87
5. Step 5: Solve for x
   x = 5,111,702.87/2,665.35
6. Step 6: Final answer
   x = 1,917.84