Finding the Fourth Proportional to 2,120.98, 3,181.34 and 659.92

Step by Step Solution

1. Step 1: Write the proportion equation
   2,120.98 : 3,181.34 = 659.92 : x
2. Step 2: Convert to fraction form
   2,120.98/3,181.34 = 659.92/x
3. Step 3: Cross multiply
   2,120.98x = 3,181.34 × 659.92
4. Step 4: Simplify right side
   2,120.98x = 2,099,429.89
5. Step 5: Solve for x
   x = 2,099,429.89/2,120.98
6. Step 6: Final answer
   x = 989.84