Finding the Fourth Proportional to 2,290.86, 3,428.69 and 2,085.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,290.86 : 3,428.69 = 2,085.90 : x
2. Step 2: Convert to fraction form
   2,290.86/3,428.69 = 2,085.90/x
3. Step 3: Cross multiply
   2,290.86x = 3,428.69 × 2,085.90
4. Step 4: Simplify right side
   2,290.86x = 7,151,894.04
5. Step 5: Solve for x
   x = 7,151,894.04/2,290.86
6. Step 6: Final answer
   x = 3,121.93