Finding the Fourth Proportional to 2,111.55, 3,166.62 and 878.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.55 : 3,166.62 = 878.28 : x
2. Step 2: Convert to fraction form
   2,111.55/3,166.62 = 878.28/x
3. Step 3: Cross multiply
   2,111.55x = 3,166.62 × 878.28
4. Step 4: Simplify right side
   2,111.55x = 2,781,179.01
5. Step 5: Solve for x
   x = 2,781,179.01/2,111.55
6. Step 6: Final answer
   x = 1,317.13