Finding the Fourth Proportional to 2,147.85, 3,220.83 and 993.60

Step by Step Solution

1. Step 1: Write the proportion equation
   2,147.85 : 3,220.83 = 993.60 : x
2. Step 2: Convert to fraction form
   2,147.85/3,220.83 = 993.60/x
3. Step 3: Cross multiply
   2,147.85x = 3,220.83 × 993.60
4. Step 4: Simplify right side
   2,147.85x = 3,200,216.69
5. Step 5: Solve for x
   x = 3,200,216.69/2,147.85
6. Step 6: Final answer
   x = 1,489.96