Finding the Fourth Proportional to 2,115.10, 3,171.82 and 728.18

Step by Step Solution

1. Step 1: Write the proportion equation
   2,115.10 : 3,171.82 = 728.18 : x
2. Step 2: Convert to fraction form
   2,115.10/3,171.82 = 728.18/x
3. Step 3: Cross multiply
   2,115.10x = 3,171.82 × 728.18
4. Step 4: Simplify right side
   2,115.10x = 2,309,655.89
5. Step 5: Solve for x
   x = 2,309,655.89/2,115.10
6. Step 6: Final answer
   x = 1,091.98