Finding the Fourth Proportional to 2,721.78, 3,756.42 and 1,978.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,721.78 : 3,756.42 = 1,978.20 : x
2. Step 2: Convert to fraction form
   2,721.78/3,756.42 = 1,978.20/x
3. Step 3: Cross multiply
   2,721.78x = 3,756.42 × 1,978.20
4. Step 4: Simplify right side
   2,721.78x = 7,430,950.04
5. Step 5: Solve for x
   x = 7,430,950.04/2,721.78
6. Step 6: Final answer
   x = 2,730.18