Finding the Fourth Proportional to 3,781.20, 5,640.36 and 3,720.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,781.20 : 5,640.36 = 3,720.72 : x
2. Step 2: Convert to fraction form
   3,781.20/5,640.36 = 3,720.72/x
3. Step 3: Cross multiply
   3,781.20x = 5,640.36 × 3,720.72
4. Step 4: Simplify right side
   3,781.20x = 20,986,200.26
5. Step 5: Solve for x
   x = 20,986,200.26/3,781.20
6. Step 6: Final answer
   x = 5,550.14