Finding the Fourth Proportional to 2,111.34, 3,163.59 and 1,287.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.34 : 3,163.59 = 1,287.12 : x
2. Step 2: Convert to fraction form
   2,111.34/3,163.59 = 1,287.12/x
3. Step 3: Cross multiply
   2,111.34x = 3,163.59 × 1,287.12
4. Step 4: Simplify right side
   2,111.34x = 4,071,919.96
5. Step 5: Solve for x
   x = 4,071,919.96/2,111.34
6. Step 6: Final answer
   x = 1,928.60