Finding the Fourth Proportional to 2,665.76, 3,999.02 and 1,279.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,665.76 : 3,999.02 = 1,279.78 : x
2. Step 2: Convert to fraction form
   2,665.76/3,999.02 = 1,279.78/x
3. Step 3: Cross multiply
   2,665.76x = 3,999.02 × 1,279.78
4. Step 4: Simplify right side
   2,665.76x = 5,117,865.82
5. Step 5: Solve for x
   x = 5,117,865.82/2,665.76
6. Step 6: Final answer
   x = 1,919.85