Finding the Fourth Proportional to 2,144.80, 3,216.72 and 989.44

Step by Step Solution

1. Step 1: Write the proportion equation
   2,144.80 : 3,216.72 = 989.44 : x
2. Step 2: Convert to fraction form
   2,144.80/3,216.72 = 989.44/x
3. Step 3: Cross multiply
   2,144.80x = 3,216.72 × 989.44
4. Step 4: Simplify right side
   2,144.80x = 3,182,751.44
5. Step 5: Solve for x
   x = 3,182,751.44/2,144.80
6. Step 6: Final answer
   x = 1,483.94