Finding the Fourth Proportional to 5,561.21, 7,663.87 and 3,986.57

Step by Step Solution

1. Step 1: Write the proportion equation
   5,561.21 : 7,663.87 = 3,986.57 : x
2. Step 2: Convert to fraction form
   5,561.21/7,663.87 = 3,986.57/x
3. Step 3: Cross multiply
   5,561.21x = 7,663.87 × 3,986.57
4. Step 4: Simplify right side
   5,561.21x = 30,552,554.23
5. Step 5: Solve for x
   x = 30,552,554.23/5,561.21
6. Step 6: Final answer
   x = 5,493.87