Finding the Fourth Proportional to 2,085.20, 3,128.60 and 1,264.06

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.20 : 3,128.60 = 1,264.06 : x
2. Step 2: Convert to fraction form
   2,085.20/3,128.60 = 1,264.06/x
3. Step 3: Cross multiply
   2,085.20x = 3,128.60 × 1,264.06
4. Step 4: Simplify right side
   2,085.20x = 3,954,722.47
5. Step 5: Solve for x
   x = 3,954,722.47/2,085.20
6. Step 6: Final answer
   x = 1,896.57