Finding the Fourth Proportional to 1,687.29, 2,327.61 and 1,128.51

Step by Step Solution

1. Step 1: Write the proportion equation
   1,687.29 : 2,327.61 = 1,128.51 : x
2. Step 2: Convert to fraction form
   1,687.29/2,327.61 = 1,128.51/x
3. Step 3: Cross multiply
   1,687.29x = 2,327.61 × 1,128.51
4. Step 4: Simplify right side
   1,687.29x = 2,626,731.16
5. Step 5: Solve for x
   x = 2,626,731.16/1,687.29
6. Step 6: Final answer
   x = 1,556.78