Finding the Fourth Proportional to 3,986.10, 5,978.94 and 1,212.71

Step by Step Solution

1. Step 1: Write the proportion equation
   3,986.10 : 5,978.94 = 1,212.71 : x
2. Step 2: Convert to fraction form
   3,986.10/5,978.94 = 1,212.71/x
3. Step 3: Cross multiply
   3,986.10x = 5,978.94 × 1,212.71
4. Step 4: Simplify right side
   3,986.10x = 7,250,690.43
5. Step 5: Solve for x
   x = 7,250,690.43/3,986.10
6. Step 6: Final answer
   x = 1,818.99