Finding the Fourth Proportional to 2,128.72, 3,189.66 and 1,397.74

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.72 : 3,189.66 = 1,397.74 : x
2. Step 2: Convert to fraction form
   2,128.72/3,189.66 = 1,397.74/x
3. Step 3: Cross multiply
   2,128.72x = 3,189.66 × 1,397.74
4. Step 4: Simplify right side
   2,128.72x = 4,458,315.37
5. Step 5: Solve for x
   x = 4,458,315.37/2,128.72
6. Step 6: Final answer
   x = 2,094.36