Finding the Fourth Proportional to 2,631.82, 3,946.56 and 987.21

Step by Step Solution

1. Step 1: Write the proportion equation
   2,631.82 : 3,946.56 = 987.21 : x
2. Step 2: Convert to fraction form
   2,631.82/3,946.56 = 987.21/x
3. Step 3: Cross multiply
   2,631.82x = 3,946.56 × 987.21
4. Step 4: Simplify right side
   2,631.82x = 3,896,095.83
5. Step 5: Solve for x
   x = 3,896,095.83/2,631.82
6. Step 6: Final answer
   x = 1,480.38