Finding the Fourth Proportional to 2,158.56, 2,978.88 and 1,214.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,158.56 : 2,978.88 = 1,214.40 : x
2. Step 2: Convert to fraction form
   2,158.56/2,978.88 = 1,214.40/x
3. Step 3: Cross multiply
   2,158.56x = 2,978.88 × 1,214.40
4. Step 4: Simplify right side
   2,158.56x = 3,617,551.87
5. Step 5: Solve for x
   x = 3,617,551.87/2,158.56
6. Step 6: Final answer
   x = 1,675.91