Finding the Fourth Proportional to 2,631.90, 3,944.82 and 987.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,631.90 : 3,944.82 = 987.40 : x
2. Step 2: Convert to fraction form
   2,631.90/3,944.82 = 987.40/x
3. Step 3: Cross multiply
   2,631.90x = 3,944.82 × 987.40
4. Step 4: Simplify right side
   2,631.90x = 3,895,118.35
5. Step 5: Solve for x
   x = 3,895,118.35/2,631.90
6. Step 6: Final answer
   x = 1,479.96