Finding the Fourth Proportional to 2,086.16, 3,130.38 and 853.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.16 : 3,130.38 = 853.28 : x
2. Step 2: Convert to fraction form
   2,086.16/3,130.38 = 853.28/x
3. Step 3: Cross multiply
   2,086.16x = 3,130.38 × 853.28
4. Step 4: Simplify right side
   2,086.16x = 2,671,090.65
5. Step 5: Solve for x
   x = 2,671,090.65/2,086.16
6. Step 6: Final answer
   x = 1,280.39