Finding the Fourth Proportional to 2,111.20, 3,172.20 and 1,873.60

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.20 : 3,172.20 = 1,873.60 : x
2. Step 2: Convert to fraction form
   2,111.20/3,172.20 = 1,873.60/x
3. Step 3: Cross multiply
   2,111.20x = 3,172.20 × 1,873.60
4. Step 4: Simplify right side
   2,111.20x = 5,943,433.92
5. Step 5: Solve for x
   x = 5,943,433.92/2,111.20
6. Step 6: Final answer
   x = 2,815.19