Finding the Fourth Proportional to 2,128.37, 2,936.46 and 1,288.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.37 : 2,936.46 = 1,288.80 : x
2. Step 2: Convert to fraction form
   2,128.37/2,936.46 = 1,288.80/x
3. Step 3: Cross multiply
   2,128.37x = 2,936.46 × 1,288.80
4. Step 4: Simplify right side
   2,128.37x = 3,784,509.65
5. Step 5: Solve for x
   x = 3,784,509.65/2,128.37
6. Step 6: Final answer
   x = 1,778.13