Finding the Fourth Proportional to 2,142.05, 3,213.16 and 681.05

Step by Step Solution

1. Step 1: Write the proportion equation
   2,142.05 : 3,213.16 = 681.05 : x
2. Step 2: Convert to fraction form
   2,142.05/3,213.16 = 681.05/x
3. Step 3: Cross multiply
   2,142.05x = 3,213.16 × 681.05
4. Step 4: Simplify right side
   2,142.05x = 2,188,328.95
5. Step 5: Solve for x
   x = 2,188,328.95/2,142.05
6. Step 6: Final answer
   x = 1,021.61