Finding the Fourth Proportional to 1,128.15, 1,690.35 and 1,085.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.15 : 1,690.35 = 1,085.49 : x
2. Step 2: Convert to fraction form
   1,128.15/1,690.35 = 1,085.49/x
3. Step 3: Cross multiply
   1,128.15x = 1,690.35 × 1,085.49
4. Step 4: Simplify right side
   1,128.15x = 1,834,858.02
5. Step 5: Solve for x
   x = 1,834,858.02/1,128.15
6. Step 6: Final answer
   x = 1,626.43