Finding the Fourth Proportional to 2,111.76, 3,168.18 and 879.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.76 : 3,168.18 = 879.72 : x
2. Step 2: Convert to fraction form
   2,111.76/3,168.18 = 879.72/x
3. Step 3: Cross multiply
   2,111.76x = 3,168.18 × 879.72
4. Step 4: Simplify right side
   2,111.76x = 2,787,111.31
5. Step 5: Solve for x
   x = 2,787,111.31/2,111.76
6. Step 6: Final answer
   x = 1,319.80