Finding the Fourth Proportional to 2,128.80, 3,174.40 and 1,869.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.80 : 3,174.40 = 1,869.86 : x
2. Step 2: Convert to fraction form
   2,128.80/3,174.40 = 1,869.86/x
3. Step 3: Cross multiply
   2,128.80x = 3,174.40 × 1,869.86
4. Step 4: Simplify right side
   2,128.80x = 5,935,683.58
5. Step 5: Solve for x
   x = 5,935,683.58/2,128.80
6. Step 6: Final answer
   x = 2,788.28