Finding the Fourth Proportional to 2,151.12, 3,218.58 and 1,315.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,151.12 : 3,218.58 = 1,315.20 : x
2. Step 2: Convert to fraction form
   2,151.12/3,218.58 = 1,315.20/x
3. Step 3: Cross multiply
   2,151.12x = 3,218.58 × 1,315.20
4. Step 4: Simplify right side
   2,151.12x = 4,233,076.42
5. Step 5: Solve for x
   x = 4,233,076.42/2,151.12
6. Step 6: Final answer
   x = 1,967.85