Finding the Fourth Proportional to 2,128.85, 3,189.32 and 1,155.77

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.85 : 3,189.32 = 1,155.77 : x
2. Step 2: Convert to fraction form
   2,128.85/3,189.32 = 1,155.77/x
3. Step 3: Cross multiply
   2,128.85x = 3,189.32 × 1,155.77
4. Step 4: Simplify right side
   2,128.85x = 3,686,114.60
5. Step 5: Solve for x
   x = 3,686,114.60/2,128.85
6. Step 6: Final answer
   x = 1,731.51