Finding the Fourth Proportional to 3,987.72, 5,505.48 and 2,809.98

Step by Step Solution

1. Step 1: Write the proportion equation
   3,987.72 : 5,505.48 = 2,809.98 : x
2. Step 2: Convert to fraction form
   3,987.72/5,505.48 = 2,809.98/x
3. Step 3: Cross multiply
   3,987.72x = 5,505.48 × 2,809.98
4. Step 4: Simplify right side
   3,987.72x = 15,470,288.69
5. Step 5: Solve for x
   x = 15,470,288.69/3,987.72
6. Step 6: Final answer
   x = 3,879.48