Finding the Fourth Proportional to 2,891.76, 3,969.72 and 2,819.28

Step by Step Solution

1. Step 1: Write the proportion equation
   2,891.76 : 3,969.72 = 2,819.28 : x
2. Step 2: Convert to fraction form
   2,891.76/3,969.72 = 2,819.28/x
3. Step 3: Cross multiply
   2,891.76x = 3,969.72 × 2,819.28
4. Step 4: Simplify right side
   2,891.76x = 11,191,752.20
5. Step 5: Solve for x
   x = 11,191,752.20/2,891.76
6. Step 6: Final answer
   x = 3,870.22