Finding the Fourth Proportional to 2,631.10, 3,945.30 and 986.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,631.10 : 3,945.30 = 986.80 : x
2. Step 2: Convert to fraction form
   2,631.10/3,945.30 = 986.80/x
3. Step 3: Cross multiply
   2,631.10x = 3,945.30 × 986.80
4. Step 4: Simplify right side
   2,631.10x = 3,893,222.04
5. Step 5: Solve for x
   x = 3,893,222.04/2,631.10
6. Step 6: Final answer
   x = 1,479.69