Finding the Fourth Proportional to 2,129.78, 3,196.76 and 1,399.88

Step by Step Solution

1. Step 1: Write the proportion equation
   2,129.78 : 3,196.76 = 1,399.88 : x
2. Step 2: Convert to fraction form
   2,129.78/3,196.76 = 1,399.88/x
3. Step 3: Cross multiply
   2,129.78x = 3,196.76 × 1,399.88
4. Step 4: Simplify right side
   2,129.78x = 4,475,080.39
5. Step 5: Solve for x
   x = 4,475,080.39/2,129.78
6. Step 6: Final answer
   x = 2,101.19