Finding the Fourth Proportional to 2,085.69, 2,861.28 and 2,031.21

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.69 : 2,861.28 = 2,031.21 : x
2. Step 2: Convert to fraction form
   2,085.69/2,861.28 = 2,031.21/x
3. Step 3: Cross multiply
   2,085.69x = 2,861.28 × 2,031.21
4. Step 4: Simplify right side
   2,085.69x = 5,811,860.55
5. Step 5: Solve for x
   x = 5,811,860.55/2,085.69
6. Step 6: Final answer
   x = 2,786.54