Finding the Fourth Proportional to 2,665.42, 3,998.88 and 910.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,665.42 : 3,998.88 = 910.80 : x
2. Step 2: Convert to fraction form
   2,665.42/3,998.88 = 910.80/x
3. Step 3: Cross multiply
   2,665.42x = 3,998.88 × 910.80
4. Step 4: Simplify right side
   2,665.42x = 3,642,179.90
5. Step 5: Solve for x
   x = 3,642,179.90/2,665.42
6. Step 6: Final answer
   x = 1,366.46