Finding the Fourth Proportional to 2,631.98, 3,948.38 and 989.91

Step by Step Solution

1. Step 1: Write the proportion equation
   2,631.98 : 3,948.38 = 989.91 : x
2. Step 2: Convert to fraction form
   2,631.98/3,948.38 = 989.91/x
3. Step 3: Cross multiply
   2,631.98x = 3,948.38 × 989.91
4. Step 4: Simplify right side
   2,631.98x = 3,908,535.90
5. Step 5: Solve for x
   x = 3,908,535.90/2,631.98
6. Step 6: Final answer
   x = 1,485.02