Finding the Fourth Proportional to 2,155.90, 2,978.14 and 1,664.74

Step by Step Solution

1. Step 1: Write the proportion equation
   2,155.90 : 2,978.14 = 1,664.74 : x
2. Step 2: Convert to fraction form
   2,155.90/2,978.14 = 1,664.74/x
3. Step 3: Cross multiply
   2,155.90x = 2,978.14 × 1,664.74
4. Step 4: Simplify right side
   2,155.90x = 4,957,821.43
5. Step 5: Solve for x
   x = 4,957,821.43/2,155.90
6. Step 6: Final answer
   x = 2,299.65