Finding the Fourth Proportional to 2,160.78, 2,981.49 and 1,276.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,160.78 : 2,981.49 = 1,276.86 : x
2. Step 2: Convert to fraction form
   2,160.78/2,981.49 = 1,276.86/x
3. Step 3: Cross multiply
   2,160.78x = 2,981.49 × 1,276.86
4. Step 4: Simplify right side
   2,160.78x = 3,806,945.32
5. Step 5: Solve for x
   x = 3,806,945.32/2,160.78
6. Step 6: Final answer
   x = 1,761.84