Finding the Fourth Proportional to 3,986.40, 5,978.34 and 3,689.94

Step by Step Solution

1. Step 1: Write the proportion equation
   3,986.40 : 5,978.34 = 3,689.94 : x
2. Step 2: Convert to fraction form
   3,986.40/5,978.34 = 3,689.94/x
3. Step 3: Cross multiply
   3,986.40x = 5,978.34 × 3,689.94
4. Step 4: Simplify right side
   3,986.40x = 22,059,715.90
5. Step 5: Solve for x
   x = 22,059,715.90/3,986.40
6. Step 6: Final answer
   x = 5,533.74