Finding the Fourth Proportional to 2,158.16, 2,978.17 and 1,213.97

Step by Step Solution

1. Step 1: Write the proportion equation
   2,158.16 : 2,978.17 = 1,213.97 : x
2. Step 2: Convert to fraction form
   2,158.16/2,978.17 = 1,213.97/x
3. Step 3: Cross multiply
   2,158.16x = 2,978.17 × 1,213.97
4. Step 4: Simplify right side
   2,158.16x = 3,615,391.11
5. Step 5: Solve for x
   x = 3,615,391.11/2,158.16
6. Step 6: Final answer
   x = 1,675.22