Finding the Fourth Proportional to 2,128.60, 3,189.30 and 1,761.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.60 : 3,189.30 = 1,761.40 : x
2. Step 2: Convert to fraction form
   2,128.60/3,189.30 = 1,761.40/x
3. Step 3: Cross multiply
   2,128.60x = 3,189.30 × 1,761.40
4. Step 4: Simplify right side
   2,128.60x = 5,617,633.02
5. Step 5: Solve for x
   x = 5,617,633.02/2,128.60
6. Step 6: Final answer
   x = 2,639.12