Finding the Fourth Proportional to 2,120.73, 3,180.63 and 659.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,120.73 : 3,180.63 = 659.55 : x
2. Step 2: Convert to fraction form
   2,120.73/3,180.63 = 659.55/x
3. Step 3: Cross multiply
   2,120.73x = 3,180.63 × 659.55
4. Step 4: Simplify right side
   2,120.73x = 2,097,784.52
5. Step 5: Solve for x
   x = 2,097,784.52/2,120.73
6. Step 6: Final answer
   x = 989.18