Finding the Fourth Proportional to 2,085.74, 3,128.71 and 699.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.74 : 3,128.71 = 699.12 : x
2. Step 2: Convert to fraction form
   2,085.74/3,128.71 = 699.12/x
3. Step 3: Cross multiply
   2,085.74x = 3,128.71 × 699.12
4. Step 4: Simplify right side
   2,085.74x = 2,187,343.74
5. Step 5: Solve for x
   x = 2,187,343.74/2,085.74
6. Step 6: Final answer
   x = 1,048.71