Finding the Fourth Proportional to 3,760.58, 5,640.31 and 987.30

Step by Step Solution

1. Step 1: Write the proportion equation
   3,760.58 : 5,640.31 = 987.30 : x
2. Step 2: Convert to fraction form
   3,760.58/5,640.31 = 987.30/x
3. Step 3: Cross multiply
   3,760.58x = 5,640.31 × 987.30
4. Step 4: Simplify right side
   3,760.58x = 5,568,678.06
5. Step 5: Solve for x
   x = 5,568,678.06/3,760.58
6. Step 6: Final answer
   x = 1,480.80