Finding the Fourth Proportional to 2,278.42, 3,415.89 and 891.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,278.42 : 3,415.89 = 891.55 : x
2. Step 2: Convert to fraction form
   2,278.42/3,415.89 = 891.55/x
3. Step 3: Cross multiply
   2,278.42x = 3,415.89 × 891.55
4. Step 4: Simplify right side
   2,278.42x = 3,045,436.73
5. Step 5: Solve for x
   x = 3,045,436.73/2,278.42
6. Step 6: Final answer
   x = 1,336.64