Finding the Fourth Proportional to 3,990.80, 5,507.16 and 2,222.30

Step by Step Solution

1. Step 1: Write the proportion equation
   3,990.80 : 5,507.16 = 2,222.30 : x
2. Step 2: Convert to fraction form
   3,990.80/5,507.16 = 2,222.30/x
3. Step 3: Cross multiply
   3,990.80x = 5,507.16 × 2,222.30
4. Step 4: Simplify right side
   3,990.80x = 12,238,561.67
5. Step 5: Solve for x
   x = 12,238,561.67/3,990.80
6. Step 6: Final answer
   x = 3,066.69