Finding the Fourth Proportional to 2,667.40, 3,998.28 and 1,280.08

Step by Step Solution

1. Step 1: Write the proportion equation
   2,667.40 : 3,998.28 = 1,280.08 : x
2. Step 2: Convert to fraction form
   2,667.40/3,998.28 = 1,280.08/x
3. Step 3: Cross multiply
   2,667.40x = 3,998.28 × 1,280.08
4. Step 4: Simplify right side
   2,667.40x = 5,118,118.26
5. Step 5: Solve for x
   x = 5,118,118.26/2,667.40
6. Step 6: Final answer
   x = 1,918.77