Finding the Fourth Proportional to 2,685.19, 3,997.69 and 2,672.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,685.19 : 3,997.69 = 2,672.20 : x
2. Step 2: Convert to fraction form
   2,685.19/3,997.69 = 2,672.20/x
3. Step 3: Cross multiply
   2,685.19x = 3,997.69 × 2,672.20
4. Step 4: Simplify right side
   2,685.19x = 10,682,607.23
5. Step 5: Solve for x
   x = 10,682,607.23/2,685.19
6. Step 6: Final answer
   x = 3,978.35